Preparation H is a skin soothing topical ointment that come in the form of gel and cream. Preparation H is perfect for treating skin inflammation, irritation and skin flares. Preparation H should not be used when pregnant because it has some side effects. Preparation H is good for reducing redness on the face that may arise as a result of rosacea. Preparation H Side Effects It can cause dilated veins. It can cause excessive sweating. It can cause itchy skin. It can cause skin break out. It can cause eye irritation.