CBD, are also banned. Certain substances used by humans are potentially toxic to horses. One example is garlic, sometimes fed to horses as an insect repellent, but it contains N-propyl disulfide, which in horses can affect their red blood cells and can lead to Heinz body anemia. Another substance sometimes fed to horses is yogurt containing active probiotics, usually in the mistaken belief it is a digestive supplement. However, as horses cannot digest lactose, doing so can actually cause diarrhea. Examples of folk remedies that are not effective include feeding chewing tobacco or diatomaceous earth to horses as a dewormer. Neither of these has been proven to work in any empirical study. Others include a practice called gingering alleged to make a horse appear more energetic, but any behavioral changes are generally a result of discomfort caused by the treatment. Sometimes natural remedies are all that is available, particularly in the global south or other isolated remote areas. Examples include horses in certain tropical nations who have sprained tendons or ligaments are treated with rachette (Nopalea cochenillifera), castor bean leaves (Ricinus communis), aloes (Aloe vera) or leaves of wonder of the world (Kalanchoe pinnata). Natural remedies are also used to treat exercise induced pulmonary haemorrhage (EIPH) with lungwort (Pulmonaria officinalis). Other plants used in combination with conventional medications included liquorice (Glycyrrhiza glabra) root, aerial parts of mullein (Verbascum thapsus) or mallow (Althea), and comfrey (Symphytum officinalis) root. Other alternative treatments used on horses include veterinary chiropractic, acupuncture, massage therapy and similar topical, hands-on treatments analogous to those used on humans. Generally there are few studies available on the effectiveness of these as applied to horses. See also Equine nutrition Farrier Horse Horse hoof Riding instructor Notes References and further reading American Association of Equine Practitioners Emergency Care Tips accessed on October 29, 2007 American Association of Equine Practitioners Immunizations: Protect Your Horse Against Infectious Diseases accessed on October 29, 2007 American Association of Equine Practitioners Internal Parasites: Strategies for Effective Parasite Control accessed on October 29, 2007 American Association of Equine Practitioners Leg Bandages - Bandaging Your Horse's Legs accessed on October 29, 2007 Auty, I. (ed, 1998) The BHS Complete Manual of Stable Management. Buckingham: Kenilworth Press. Evans, J. Warren et al. (1990) The Horse Second Edition New York: Freeman Evans, Walter. (2000) Horses: A Guide To Selection, Care And Enjoyment. Owl Books; 3rd edition. , Harris, Susan E.