He recently found slight blood in his saliva after an episode of excess acidity. It started with him having to remove yellow coloured spit from his mouth (probably acid) and soon after there was slight blood in the saliva. It then happened again next morning after waking up from sleep. There was no blood for the remainder of the day. It again happened today after waking up from sleep. He has no other symptoms, no chest pain, no breathlessness or any other problems. Would love to know the cause of it and ways to fix it. He does not smoke and his a generally healthy person. He is not having lot of cough or anything else. The saliva is reddish pink colour and only happens after waking up not during the day. Please help.