If you’ve ever questioned whether your doctor really knows what he or she is talking about, these shocking medical practices of years gone by will give you some fodder for your suspicions.

Although they may sound unbelievable, these medically approved remedies were at one time all the rage.

1. Children’s soothing syrups. Used for teething and nursing infants, and also to “cure colic, cramps, dysentery, canker sores and pain,” these syrups were “soothing” because they contained morphine, chloroform, codeine, heroin, opium and cannabis.

2. Mercury. This toxic metal that can cause heart and lung problems, psychotic reactions, delirium, tremors, chest pain and more, was used for centuries to treat everything from cuts to constipation.

3. Heroin. If you had a cough in the late 19th century, a dose of heroin would fix it. This now illegal, extremely addictive drug was originally developed and sold by Bayer … as a cough suppressant.