The presence of a harmful material in the stomach will most likely cause?

The presence of a harmful material in the stomach will most likely cause nausea and vomiting. This is because the stomach is lined with a layer of mucus that helps to protect it from the acidic environment of the stomach. When a harmful material enters the stomach, it can irritate the lining of the stomach and cause inflammation. This inflammation can lead to nausea and vomiting. In some cases, a harmful material can also cause damage to the lining of the stomach, which can lead to bleeding and other complications.