chlamydia infection
"After 1 week of anal pain that I thought was a fissure I decided to go to a clinic for follow up. Lo and behold, swaps came back positive for chlamydia. (Ironically slightly relieved given the healing time of a fissure)

After two days of the doxycycline I felt mild pain when passing a stool. 4 days later about 10% of the pain remained. 7 days later, assymptomatic.

Side effects included; very mild dull headache about 3-4 hours after tablet, very loose stool throughout the entire course of administration, bloating (caffeine, lactose mainly), sunburn after 30-40 mins in direct sunlight. 
Despite these mild concerns the medication was perfect, I have almost no post treatment side effects. Try a daily clove of chopped garlic with it"