Heroin can be used in a variety of ways, depending on user preference and the purity of the drug. Heroin can be injected into a vein ("mainlining"), injected into a muscle, smoked in a water pipe or standard pipe, mixed in a marijuana joint or regular cigarette, inhaled as smoke through a straw, known as "chasing the dragon," snorted as powder via the nose.

Short-term effects of heroin abuse appear soon after a single dose and disappear in a few hours.After an injection of heroin, the user reports feeling a surge of euphoria ("rush") accompanied by a warm flushing of the skin, a dry mouth, and heavy extremities. Following this initial euphoria, the user goes "on the nod," an alternately wakeful and drowsy state. Mental functioning becomes clouded due to the depression of the central nervous system. Other effects included slowed and slurred speech, slow gait, constricted pupils, droopy eyelids, impaired night vision, vomiting, constipation.