How to Tell If Someone Is on Cocaine: Signs and Symptoms

Medical Review: Brandon McNally, RN | Published: July 25, 2026 | Last Updated: July 25, 2026

Quick answer: The clearest signs of cocaine use are dilated pupils, a persistently runny or congested nose, unusual talkativeness and confidence, and long stretches without sleep. But most families do not catch someone using — they notice the crash afterwards: sleeping for twelve or more hours, eating enormously, and being flat and irritable for days.

If someone has chest pain, a racing or irregular heartbeat, a seizure, a very high temperature, severe confusion, or becomes unresponsive, call 911 immediately. Tell responders what was taken — treatment for cocaine-related cardiac events differs from standard care. Because cocaine is frequently contaminated with fentanyl, give naloxone if it is available; it is safe even if opioids are not involved.

Key Takeaways

Dilated pupils are the most reliable physical sign during use — cocaine widens the pupils, unlike opioids, which shrink them.
Families usually notice the crash rather than the high, and often mistake it for depression, burnout, or flu.
The pattern matters more than any single sign: repetition, timing, and money are more telling than pupils.
Every sign on this page has other explanations, and a wrong accusation costs you the conversation you will need later.
Do not confront someone while they are actively high — agitation and paranoia make that unsafe and unproductive.
What you do with what you notice matters more than how certain you are.

What Cocaine Does to the Pupils

Cocaine causes mydriasis — pupil dilation. It blocks the reuptake of norepinephrine, which drives the sympathetic nervous system into the same state it enters under threat, and one component of that state is the pupil opening wide.

What you would see is pupils noticeably larger than the light in the room accounts for, sometimes to the point where the coloured iris looks like a thin ring. The dilation lasts roughly as long as the drug is active and fades as the effects wear off.

The useful contrast: stimulants dilate, opioids constrict. Cocaine, methamphetamine, and prescription stimulants widen the pupils. Heroin, fentanyl, and prescription opioids shrink them to pinpoints. If you are trying to work out which category of substance you may be looking at, this is the single most informative physical sign.

One caution that matters. Pupil size is affected by lighting, emotional state, tiredness, anxiety, several common medications including some antidepressants, migraine, eye drops, and simple individual variation. Dilated pupils in a dim room mean nothing at all. Dilated pupils in bright light, alongside other changes, mean something.

Other Physical Signs

Runny or congested nose that does not respond to allergy treatment and never quite clears. Frequent sniffing is one of the most commonly noticed signs.
Nosebleeds, particularly recurring ones. The nasal progression is covered in Coke Nose: How Cocaine Damages the Nose and When It Becomes Irreversible.
Loss of appetite and weight loss during use, followed by ravenous eating afterwards.
Long periods without sleep, then extended catch-up sleep.
Restlessness — jaw tension, teeth grinding, fidgeting, an inability to sit still.
Sweating and raised body temperature without exertion or fever.
Frequent short absences — repeatedly leaving the room, the table, or the party for a few minutes at a time.

Behavioural Signs

During use, people are typically talkative in a way that outruns the conversation, confident to the point of grandiosity, and full of plans. Some become irritable or argumentative instead, especially later in a session or on higher doses.

Other patterns worth noticing:

Sudden energy and sociability late at night, particularly after a flat evening
Talking rapidly, interrupting, jumping between subjects
Unusual secrecy about phone, plans, or whereabouts
New friendships that seem to exist entirely outside the rest of their life
Suspicion or paranoia — feeling watched, misreading ordinary remarks as attacks
Mood that swings hard within a single evening

The Timing Pattern

This is where recognition actually happens, and it is the part most lists leave out.

Individual signs are ambiguous. Patterns are not. Cocaine use tends to cluster around money and around opportunity — paydays, Fridays, nights out, times when the house is empty. What families eventually notice is not a symptom but a rhythm: the same disappearance, the same late night, the same wiped-out weekend, arriving on the same schedule.

If you find yourself able to predict which nights will be strange, that prediction is more meaningful than anything you would see in someone's eyes.

The Crash — What You Are Most Likely to Actually See

Most people never witness someone using. What they witness is the day after, and they frequently misidentify it.

The crash follows a cocaine session as dopamine stores deplete. It looks like:

Sleeping twelve hours or more and still waking exhausted
Eating enormously
Flat, joyless mood — nothing lands, nothing is funny
Irritability out of proportion to what is happening
Withdrawal from everyone, sometimes for two or three days

Families routinely read this as depression, burnout, glandular fever, or "just being difficult." What distinguishes it is the cycle: recovery over a few days, a period of normality, then the same collapse again on the same kind of schedule. Depression does not usually run on a weekly rhythm tied to Fridays.

The full sequence, including what happens if someone stops, is set out in Cocaine Withdrawal Timeline: What to Expect in Detox.

Money

Cocaine is expensive and use tends to escalate, so financial signs often appear before physical ones become undeniable — and they are harder to explain away.

Cash withdrawn frequently in small amounts, money borrowed with vague reasons, unexplained shortfalls, bills going unpaid while spending continues, items missing from the house, defensiveness about anything financial. Where use has been going on for a while, this is often the evidence that finally makes the picture unambiguous.

What Else Could Explain the Same Signs

This section exists because getting it wrong is expensive.

Dilated pupils can be caused by low light, anxiety, tiredness, migraine, eye drops, several antidepressants and other medications, and by other stimulants including prescribed ADHD treatment. A chronically runny nose can be allergies, a deviated septum, or overuse of decongestant spray. Weight loss, poor sleep, irritability, and social withdrawal are all features of depression, anxiety, thyroid disease, and ordinary sustained stress. Erratic sleep and mood swings can be bipolar disorder.

None of this means you are wrong. It means a single sign is not evidence, and that if you accuse someone based on one, and you are wrong, you will have spent trust that you would have needed later if you turn out to be right.

What holds up is the pattern: several signs, repeating, on a rhythm, alongside money that does not add up.

What Not to Do

Do not confront someone who is currently high. Cocaine intoxication can involve agitation, paranoia, and poor impulse control. Nothing you say will be retained and the situation can turn unsafe. Wait.
Do not lead with an accusation. "You're using, aren't you" produces a denial that both of you then have to defend.
Do not search their belongings as a first step. If you are found out before you have said anything, the conversation becomes about your behaviour rather than theirs.
Do not issue a threat you will not carry out. One unenforced ultimatum costs you every subsequent one.
Do not do this alone if you can avoid it. One frightened person against a denial rarely gets anywhere.

What to Do Instead

Write down what you have actually observed — dates, behaviours, amounts. Specifics are much harder to argue with than impressions, and the act of writing it clarifies whether you have a pattern or a worry.

Choose a sober moment. Not mid-crash, not mid-session. A flat weekday is better than a confrontation in the middle of something.

Lead with what you have seen and how it affects you, not with a diagnosis. "You've been sleeping through Sundays and I've noticed money going missing, and I'm frightened" is harder to deflect than "you're on coke."

Expect denial and do not treat it as the end. Denial is the ordinary first response. It is not a verdict on whether the conversation worked.

Get advice before a bigger conversation. If several people are worried, a structured intervention with professional guidance is considerably more likely to work than an ambush at a family gathering — and considerably less likely to cause lasting damage if it does not.

Emergency Signs

Call 911 immediately for any of these, during or after use:

Chest pain, or pain spreading to the arm or jaw
Racing, pounding, or irregular heartbeat
Seizure
Very high body temperature, hot dry skin, or extreme confusion
Sudden severe headache, facial droop, weakness on one side, or slurred speech
Severe agitation or hallucinations
Unresponsiveness, or breathing that slows or stops

Cocaine causes heart attacks and strokes in young people with no prior cardiac disease, and the supply is frequently contaminated with fentanyl. Naloxone reverses opioid overdose, is available without a prescription, and is safe to give even if it turns out no opioid was involved. Tell responders what was taken — withholding it makes treatment less safe, and nobody is going to be arrested for the disclosure.

Frequently Asked Questions

What do cocaine pupils look like?

Noticeably dilated — wide enough that the coloured part of the eye can look like a thin ring — and not shrinking as much as expected in bright light. Dilation lasts roughly as long as the drug is active.

Does cocaine make your pupils big or small?

Big. Cocaine and other stimulants dilate the pupils. Opioids such as heroin and fentanyl do the opposite and constrict them to pinpoints, which is a useful way to tell the two categories apart.

How long do pupils stay dilated after cocaine?

Broadly as long as the effects last, then fading as the drug clears. Because cocaine's effects are short, dilation is a sign of recent use rather than of use in general — someone can have used yesterday and have entirely normal pupils today.

How can you tell if someone is high on cocaine right now?

Dilated pupils, rapid and pressured speech, unusual confidence or irritability, restlessness, sweating, repeated short absences, and no interest in food or sleep. It is generally not the moment to raise it.

What are the signs of cocaine use the next day?

The crash: long heavy sleep, big appetite, flat mood, irritability, and social withdrawal for one to three days. This is what families most often see, and it is regularly mistaken for depression or illness.

Can you tell if someone is using cocaine without a drug test?

You can build a well-founded suspicion from a repeating pattern, but no combination of outward signs is proof. Detection windows for testing are covered in How Long Does Cocaine Stay in Your System? Test Windows.

What should I do if I think my partner or child is using cocaine?

Write down what you have observed, pick a sober moment, describe the behaviour and its effect on you rather than making an accusation, and expect denial without treating it as failure. If several people are concerned, get professional guidance before a group conversation.

Is it safe to confront someone who is high on cocaine?

No. Intoxication can bring agitation, paranoia, and poor impulse control, so the conversation is unlikely to be remembered and can become unsafe. Wait for a sober moment.

Getting Help

Noticing is the hard part, and you have done it. What follows is usually harder, because the person you are worried about may not agree with you for some time.

You do not have to wait for them to be ready before you get advice yourself. Families frequently spend months rehearsing a conversation that a professional could help them structure in an afternoon — and the way a first conversation goes has a real effect on what is possible afterwards.

Intervention New York works with families on structured intervention and placement, including cases where previous conversations have already gone badly. For treatment options and confidential placement, Cocaine Addiction Treatment on Long Island provides navigation support and insurance verification.

If you are unsure whether what you are seeing warrants any of this, that uncertainty is itself a reasonable reason to ask someone.

Related Guides

References

About the Author

Benjamin Zohar, NCACIP, is a Nationally Certified Advanced Clinical Intervention Professional and ISSUP network moderator specializing in addiction intervention, treatment navigation and emerging substance-use risks.

He publishes evidence-informed resources addressing counterfeit medications, fentanyl exposure, benzodiazepine safety, kratom dependence and concentrated 7-hydroxymitragynine products. His work published through ISSUP has been cited or referenced by GoodRx, The Washington Post, WIRED and Newsweek.

Written by: Benjamin Zohar, NCACIP

Medical Review

Medically reviewed by: Brandon McNally, RN

Medical Disclaimer

This article is intended for educational and public-health purposes. It does not provide individualized medical advice, diagnosis or a tapering schedule. Do not start, stop or alter a prescription medication without consulting a qualified healthcare professional. Call emergency services for seizures, difficulty breathing, loss of consciousness, severe confusion or other life-threatening symptoms.

International Intervention Specialists (IIS)