Kitty, please take it with food. It can cause ulcers if taken on an empty stomach - please make sure you eat something (a bowl of oatmeal, a breakfast sandwich, something like that - not just a cup of coffee or tea) before you take the Advil, and then take it with milk if you like milk. If you need to take it with coffee or tea (on top of food) please put milk in the coffee or tea. Please don't take it with anything acidic, like orange juice or lemonade or cola.
Ibuprofen (Advil) is an NSAID (non-steroidal anti-inflammatory drug) and NSAIDs are known to cause ulcers. Here's a link to helpful info from the UK's National Health Service:
https://www.nhs.uk/conditions/stomach-ulcer/causes/
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