I have a 1.5 years old cat and since his surgery he is having diarrhea... I do not know what to do... Can some one help me please...
Thanks... his surgery was 2.5 month ago...

Have you called and asked your vet?

This is just a guess, but it could be his organs are trying to adjust after the surgery... what kind of surgery did he get?

What kind of surgery did he have?

2.5 months is usually plenty of time to get over a surgery.

I didn't quite understand you question though.. has he been having diarreah for the whole 2.5 months or is it only recently?

What are you feeding?

Has he had a check up since the surgery?

In the meantime make sure he is getting PLENTY of fluids as having diarreah can dehydrate him quickly and can be very dangerous.