A doctor (vejja) is a person who has been trained in and who practices the science of medicine. Because of his concern for human happiness the Buddha frequently addressed issues relevant to the medical profession. He listed eight causes of sickness (Samyutta Nikaya 4. 230), he suggested that one’s outlook and attitude might have a part to play in healing (Anguttara Nikaya 3. 144) and mentioned that one could maintain psychological well-being despite being physically sick (Samyutta Nikaya 3. 2). In what could form the basis of a Buddhist equivalent to the Hippocratic Oath, he once said; ‘One who cares for the sick is fit to do so if he has five qualities. What five? He can prepare medicine, he knows what is healing and administers it but never administers the harmful, he cares for the patient out of love not out of desire for gain, he is unmoved by excrement, urine, vomit and spittle, and from time to time he can instruct, uplift, gladden and encourage the patient with talk on Dhamma’ (Anguttara Nikaya 3. 143). The Buddha’s teachings added certain ethical elements to the medical practices current during his time. Srushita, the father of Indian medicine, advised the physician not to treat a patient who might die so as to avoid being blamed for his or her death. By contrast, the Buddha said that a patient should be treated and nursed even if he or she is going to die, out of compassion for him or her (Anguttara Nikaya 1. 121). The Buddha was often compared to a doctor, ‘The Buddha is like a skilled physician in that he is able to heal the sickness of the defilements’ (Pj.21). Once (It.101) he even called himself, ‘the highest physician’ (anuttaro bhisakko). Buddhist monks have long served as doctors despite this being against the Vinaya. It is not known who discovered smallpox inoculation but the procedure was introduced into China by an Indian Buddhist monk named Amaritànanda in the 7th century.