Dressings can also regulate the chemical environment of a wound, usually with the aim of preventing infection by the impregnation of topical antiseptic chemicals. Commonly used antiseptics include povidone-iodine, boracic lint dressings or historically castor oil. Antibiotics are also often used with dressings to prevent bacterial infection. Medical grade honey is another antiseptic option, and there is moderate evidence that honey dressings are more effective than common antiseptic and gauze for healing infected post-operative wounds. Bioelectric dressings can be effective in attacking certain antibiotic-resistant bacteria and speeding up the healing process.