Urine is a waste property discharged from the body which contains toxic element. Nevertheless, Muhammad recommended it.
The climate of Medina did not suit some people, so the Prophet ordered them to follow his shepherd, i.e. his camels, and drink their milk and urine (as a medicine). So they followed the shepherd that is the camels and drank their milk and urine till their bodies became healthy. Then they killed the shepherd and drove away the camels. When the news reached the Prophet he sent some people in their pursuit. When they were brought, he cut their hands and feet and their eyes were branded with heated pieces of iron.
Sahih al-Bukhari 5686
Vol. 7, Book 71, Hadith 590