They dont all have problems, some have none, but the health issues noted in the breed are Ectropian, Entropian, PRA, CMR, Cataracts, Hip and Elbow Dysplasia, Bloat, Bladder stones and wobbler syndrome.
I have 2 English Mastiffs and they don't have any problems at all. I have a few problems, i.e. I need a van to transport them both together, and a large house with lots of room for their large turning circles. They are lovely gentle, loyal and very tactile dogs. They do drool after a drink or food but mine come to me to have their faces wiped.