What does marijuana do in the brain? It produces some excitatory behavioural changes, including euphoria, but it is not generally regarded as a stimulant. It can also produce some sedative effects, but not to the extent of a barbiturate or alcohol. It produces mild analgesic effects (pain relief ) as well, but this action is not related pharmacologically to the pain-relieving effects of opiates or aspirin. Finally, marijuana produces hallucinations at high doses, but its structure does not resemble LSD or any other drug formally categorized as a hallucinogen.