Oxipor VHC Coal Tar Psoriasis Lotion helps stop the itching, redness, scaling and flaking associated with psoriasis. The active ingredient in Oxipor is 25% coal tar solution (equivalent to 5% coal tar). Many people prefer Oxipor over other psoriasis treatments. Each bottle of Oxipor Coal Tar Lotion contains 4 fluid ounces of lotion (118 ml).