1 Before starting fluorouracil(cream) treatment, make sure you tell your doctor about any other medications you are taking (including prescription, over-the-counter, vitamins, herbal remedies, etc). 2  Do not take aspirin, products containing aspirin unless your doctor specifically permits this. As a topical cream or solution, a thin coating is applied to the affected skin lesions, treatment may continue over several weeks. 2  Use non-metal applicator or fingertips to apply cream. 3  Use care when applying cream or solution around the eyes, nose, and mouth.