According to dermatologist Debra Jailman (as quoted by Real Simple), it is impossible to actually shrink the pores. Pore size is genetic, but there are ways to make the pores appear smaller, such as wearing makeup and moisturizer that are noncomedogenic, exfoliating the skin often, using products that contain retinol and using a steam treatment on the face.
Noncomedogenic products are those that do not clog the pores. Avoiding products that contain mineral oil and petroleum makes the pores look smaller. Washing makeup and moisturizer from the face with a gentle cleanser each night can also give the pores a smaller appearance. Physical and chemical exfoliants are also necessary for cleansing the pores and keeping them from looking too large. Chemical peels and facial scrubs remove the dry cells on the surface of the skin, which makes pore openings shallow and causes them to be less noticeable.
Skin care products with retinol help to remove all the impurities from the pores and resurface the skin. These products also give the skin a more refreshed and youthful appearance. A stream treatment helps to draw impurities from the pores and release excess oil. Adding herbs such as lavender, rosemary and mint to a bowl of hot water and bringing the steam in contact with the face naturally moisturizes the skin and cleanses the pores.