However, for some people, these cleansers may irritate the skin and often provoke allergic responses. Swallowing excess blood can irritate the stomach and cause vomiting. However, caesium chloride powder can irritate the mucous membranes and cause asthma. As all detergents it can irritate skin and eyes. This pollen can also irritate the skin and cause contact dermatitis. This fluid may irritate eyes or skin. Dichloromethane can irritate the skin on contact and the lungs if inhaled. Niobium dust can irritate the eyes and skin. The retained blood can also irritate the pleura, causing scar tissue to form. Rubbing one's eyes can irritate them further, so should be avoided. Sodium polyacrylate itself does not irritate the skin. Nicotine itself can also irritate the mucosa. Germanium, in compounds, can sometimes irritate the eyes, skin, or lungs. Pure ethanol will irritate the skin and eyes. They are pungent when chopped and contain certain chemical substances which irritate the eyes.