Affects of steroid treatment for lung condition?

What KIND of antibiotic? 500mg of one may be not enough, or way too much of another. Edit your post, and add this info. Prednisolone can cause weight gain...and make u hungry and want to eat. They can cause ulcers if taken for a long time, but if you follow the directions on the back of the pack they came in, you will be fine. If you have bad abdominal pain, black stools, nausea/vomiting that looks like coffee grounds, call the doctor right away--those are signs of a GI bleed like an ulcer. And unless the doctor or pharmacist say otherwise, you should always eat when taking antibiotics. They can cause stomach upset because they kill the good bacteria in your gut. Eating yogurt will help replace that and calm your stomach.