Symptoms and their severity vary from person to person. Generally people with lactose intolerance will have abdominal pain, gas, cramping, a bloated feeling and diarrhea.
These symptoms may be noted within an hour after ingesting milk or other dairy products, or they can occur several days later, after the accumulation of poorly digested material.
Some people have tolerable discomfort, others are quite ill or may even have to be hospitalized. Though the degree of intensity of symptoms is enormous, abdominal distress is the common denominator.