Notice any unusual sensations of relaxation. Modest amounts of GHB can reduce feelings of anxiety and lower inhibitions. These early feelings can be similar to alcohol intoxication.
Take a walk. GHB can produce feelings of sleepiness in the early stages. Test yourself to see whether you feel unnaturally drowsy by taking a short walk.
Pay attention to feelings of nausea or slow heart rate. These symptoms can indicate that GHB has entered your body.
Smell your drink for any abnormalities. GHB doesn't always produce a scent, though it's sometimes possible to recognize a mild hint of gas, glue or salt odors.
Treat your hangover normally. Many of the symptoms and side effects of GHB poisoning are similar to an alcohol hangover. Treat headaches and stomach discomfort as you would for a hangover while testing for other abnormalities that might suggest you've ingested GHB too.
Check your heart rate. As GHB leaves your body, it can increase your heart rate and contribute to hypertension.
Make a checklist for other symptoms of GHB poisoning. It's not uncommon to suffer nausea, vomiting or increased sweating as your body recovers from GHB poisoning.
Watch out for hallucinations. In severe cases of GHB poisoning, it's possible to suffer hallucinatory visions.
Inspect your genital area for bruises or abrasions. This can be a telltale sign that you've suffered a date rape.
Check with friends to see you whether you behaved strangely the night before. GHB poisoning can affect your memory of the previous night, so your account of what happened might be very different from reality.