Heroin comes from the opium poppy. It's a powerful central nervous system depressant that can be used to relieve pain without causing a loss of consciousness. However, the drug is often abused because of its intoxicating effects. Heroin generally produces feelings of drowsiness, mental confusion, and euphoria. It can also cause both physical and psychological dependence. Many of the health problems associated with heroin abuse are caused by varying degrees of quality and quantity, and uncertain purity and dosage levels often result in a fatal overdose. Unfortunately, no matter how much experience the user has, a lethal dose is always dangerously close to the effective dose. Symptoms of a heroin overdose include shallow breathing, clammy skin, convulsions, and coma. In addition, it's particularly dangerous to combine heroin and alcohol or cocaine, and many heroin-related deaths involve the use of other drugs. Needle sharing is another danger faced by heroin addicts. This practice increases a user's risk of contracting hepatitis and HIV (H-I-V), the viral agent responsible for AIDS. To make matters worse, it's believed that heroin abuse may lower the resistance of the immune system, thereby making addicts more vulnerable to the AIDS virus. Heroin abuse by pregnant women can have severely adverse effects on the mother as well as the baby. Narcotics Anonymous is a self-help group that can provide support to heroin users and their families. For more information about heroin, please consult a health care provider.