Yotsuba Customer Care Center

Yotsuba Q&A

Why do I get an upset stomach after drinking milk?
Upset stomach may be caused by lactose intolerance, or poor physical
condition.

Carbohydrates in milk contains ‘lactose’, which is broken down in the stomach by a digestive enzyme called ‘lactase’, then absorbed into the body. If there is not enough lactase in your stomach, it may become difficult to break down and absorb lactose, resulting in conditions such as upset stomach or diarrhea.
If you have lactose intolerance, we recommend warm the milk, or drinking it in small portions to gradually get used to it. You may also consider lactose-free milk, which has been treated to break down the lactose in advance, or select milk products lower in lactose, such as cheese and yoghurt.