A gastroscopy can help rule out or confirm the presence of conditions like stomach cancer, peptic ulcers or gastritis. In this procedure, a thin, flexible tube called an endoscope is lowered down the throat to look inside the food pipe, stomach and first small of the small intestine. The endoscope has a camera and light at one end which captures and sends images of your insides to a monitor. It can also take tissue samples by latching instruments such as small pincers, as well as suck out air and fluids.