Deliriants are considered to be true hallucinogens, because the visuals they produce are hard or impossible to tell apart from reality; they are also known for negative physical effects.

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BenzydaminedelirianttentativestimulantNSAID with local anesthetic and analgesic properties, similar to Ibuprofen or Naproxen. Sometimes abused in overdose with reported delirant and stimulant effects.
Daturadepressant tentativedeliriantA family of plants containing various Tropane alkaloids. Produces long-lasting deliriant effects including very realistic and often unpleasant hallucinations along with short-term amnesia. Datura plants are toxic to humans, and potency varies greatly from plant-to-plant, making the drug extremely difficult to dose safely. Not typically regarded as recreational.
Doxylaminedepressant deliriantA first generation antihistamine and anticholinergic, originally used to treat nausea and itching, and later as a sleep aid. Causes drowsiness, and delirium in overdose. Sometimes used with opioids to combat nausea and potentiate effects.
DPHdepressant deliriantcommonAn antihistamine which, when taken in smaller doses relieves allergies and insomnia. In larger doses works as a deliriant and can actually keep the user awake. Generally the 'high' of this drug is reported as dysphoric, potentially causing hallucinations indistinguishable from reality.
Dimenhydrinatedepressant deliriantcommonA combination of diphenhydramine and a mild stimulant to counteract the drowsiness accompanied by typical medical use of diphenhydramine. Roughly half the potency of DPH. Small doses can relieve motion sickness, reduce body load from opioids or DXM. Becomes a deliriant in high doses, keeping the user awake and often causing dysphoric, realistic hallucinations.
Hydroxyzinedepressant deliriantAn antihistamine drug commonly prescribed for anxiety, itchiness, nausea, and insomnia. Hydroxyzine has also been used to potentiate the analgesia of opioids as well as diminishing the negative effects of opioids, such as itchiness.
JenkemdelirianttentativeA hoax which began in online communities of a non-existent drug which was claimed to result from a process involving human waste.
Salviadissociativedeliriantdepressant commonA plant which, when smoked, causes short but very intense psychedelic experiences. It is considered physically safe, though users of high dosages often experience bizarre other-worldly scenarios which may be confusing or terrifying.
ScopolaminedelirianttentativeThe main active compound in Datura, medium and high doses have serious side effects and cause extremely unpleasant deleriant hallucinations. Avoid it.

Factsheets on 9 drugs