I started taking Advil the last two days. I was shocked when I gained 6 pounds in two days and had hardly time to eat due to a major activity which required lots of energy. I also felt stomach boating and swelling in the ankles. I would describe this as water retention . During these two days I took 8 liquid tablets daily (200 mg.) My weight very seldom fluctuates so drastically and I attribute this to the Advil tablets.