How much milk should i allow my 3 year old to drink in a day? how much is too much? is there health risks if he drinks a gallon by himself in 2 days

NO more than 16 oz: Justin - see my answer to your other question. There can be severe nutritional deficiencies, especially severe anemia, with that amount of milk intake. 16 ounces of milk a day maximum and the rest of his fluid intake should be water only! No giving juices, Kool-Aid, smoothies - nothing but water!

Bad idea: 3 year olds should get to decide what they eat or drink on their own. Too much cow's milk can cause nutritional problems and sometimes immune problems. It had been linked to development of type 1 diabetes in some children and even some adults.

Tough habit: Cow's milk is a balanced and complete diet for a calf, not a human toddler. A child sized portion of milk (4-6oz) can be offered at mealtimes, but table food should be most of your child's calorie intake to provide enough vitamins and nutrients. Following the USDA plan of a plate of half vegetables, quarter grains and quarter protein source is a good place to start meal planning. Snack: fruit