The surgeon Sushruta may have lived about 500 BC. Sushruta wrote a book, the Samhita, explaining his surgical methods. Sushruta described how to pull teeth, how to fix broken bones, and how to fix blockages of the intestines. He didn't have any anesthesia other than wine. By about 200 AD, Indian doctors, like Chinese doctors and Greek doctors, had abandoned the idea of bad spirits in favor of the somewhat less wrong idea of dosha or humors. The doctor Charaka wrote perhaps about this time. Charaka recognized that prevention was the best cure for many diseases, and he recommended keeping your humors in balance can makes us to stay healthy. Charaka recognized three humors - bile, phlegm (snot), and wind. If your humors got out of balance, you should take medicines to rebalance them.