Mara, many people find that milk and any form of dairy can produce more acid. Not a good thing when you've got stomach issues.
MayoClinic site is one of the most reliable sources to get information. This is what it says about foods and drinks. Mentions nothing about milk, but if you're lactose intolerant, milk SHOULD NOT be consumed.
Mayoclinic says this......... Link is below for more info.
Eat smaller, more frequent meals. If you experience frequent indigestion, eat smaller, more frequent meals to help ease the effects of stomach acid.
Avoid irritating foods. Avoid foods that irritate your stomach, especially those that are spicy, acidic, fried or fatty.
Drink alcohol in moderation, if at all. Excessive use of alcohol can irritate the mucous lining of your stomach. Limit yourself to one drink per day if you're a woman or two drinks per day if you're a man.
Consider switching pain relievers. If you use pain relievers regularly, ask your doctor whether acetaminophen (Tylenol, others) may be an option for you. This medication is less likely to aggravate your stomach problem.
Manage stress. Stress may make your gastritis symptoms worse. Stress may be unavoidable, but you can learn to cope with it. If you have trouble relaxing, consider trying calming activities, such as meditation, yoga or tai chi.
http://www.mayoclinic.com/health/gastritis/DS00488/DSECTION=lifestyle%2Dand%2Dhome%2Dremedies