Abu Dawud Book 1, Hadith Number 336.

Chapter : A person who is sexually defiled is permitted to eat anything before washing.

Narated By Jabir : We set out on a journey. One of our people was hurt by a stone, that injured his head. He then had a sexual dream. He asked his fellow travellers: Do you find concession for me to perform tayammum? They said: We do not find any concession for you while you can use water. He took a bath and died. When we came o the Prophet (PBUH), the incident was reported to him. He said: They killed him, may Allah kill them! Could they not ask when they did not know? The cure of ignorance is inquiry. It was enough for him to perform tayammum and to pour some drops of water or to bind a bandage over the wound (the narrator Musa was doubtful); then he should have wiped over it and washed the rest of his body.