Wet the horse thoroughly.  When treating a horse with a thick or long coat this will take time.  Using a sprayer will also remove surface dust, dirt and loose hair.  Wet hair and skin will more readily combine with the active ingredients in the shampoo so the medication can get down where it is needed - on the skin.  Most shampoos work more effectively with warm water than cold and this is especially true of certain medicated ingredients.

    Follow the manufacturer's directions for the amount to use and the manner of application.  Some products are to be applied full strength on the horse although we generally feel dilution is the best way of distribution.  If 2 oz. is recommended, don't think that 4 oz. will clear up the problem twice as fast or that you can "leave a little on" to keep working.  The more shampoo you use, the harder it will be to rinse out completely and the more likely it will cause itching or dry skin.  Dilute the recommended amount with water in a recycled squirt bottle.

    If you're treating scratches or cannon scald or keratosis, begin applying the medicated shampoo at the knee or hock.  Press the knee backward or the point of the hock forward to lock the horse's leg in a "stand" position as you scrub the medicated shampoo all the way down the leg and into the fetlock region.  Often the skin of affected horses is understandable sensitive, so use safe bathing practices.
If you are giving an overall medicated bath, work the medicated shampoo in with a curry tool.  For routine baths, you can use a Sarvis-style curry (pictured here) that reaches down to the skin.  However, if there are breaks in the skin or the horse's skin is tender, use a soft curry with thick rubber fingers.

    When treating the mane, work your way down inch by inch.  Scrub small sections at a time, getting down to the crest by separating the hairs.  Add a small amount of water to increase suds but not so much that the suds run down the neck.  You want the medicated suds to lay on the crest.

    Especially if a horse has been rubbing his tail or hindquarters, take time to separate the tail hairs on the top of the dock as you wet and scrub.

    Wash the underside of the dock paying special attention to the skin that comes in contact with the anus and vagina.  Be sure that the shampoo you are using is safe to use on the genital areas because even if you are not specifically bathing the genitals, the shampoo will come in contact with them.

    If the horse was particularly dirty, you might need to rinse and then repeat the shampooing.  When you feel the horse is clean, lather him well and then let him stand with the shampoo "working" for 5-30 minutes depending on your veterinarian's or the manufacturer's instructions.  The horse can stand cross-tied in the wash rack or if it is still, sunny day, you can let the horse stand outside.  Use a cooler if the temperature is under 60 F or if other conditions make a chill a possibility.  This cooler should be of a material that can be quickly and easily laundered and dried (save your wool cooler for other uses) as you will want to wash the cooler after each use.  Do not use this cooler on another horse.

    Begin rinsing, starting on the high points such as the mane.  Rinse until the hair comes out "squeaky clean".  If there is the slightest slippery feel, continue rinsing.  Scrub as you rinse to activate any hidden suds.

    When rinsing the body, after the sheets of suds have subsided, you can use a hose brush to curry and rinse at the same time.  Make sure you have not left any medicated shampoo behind.

    Often a horse will START a tail rubbing habit because of an inadequately rinsed tail.  So don't spare the water here.  Be sure the water is a comfortable body temperature when rinsing the tail or you could get kicked or stepped on.  A horse often tucks his tail and squats in a reflex reaction to his tail being wetted.  When rinsing, start from the top, then separate the hairs, rinse the sides and underside.

    Use a sweat scraper or squeegee to remove the majority of the water from the horse's coat.  If, in the process, you scare up a few bubbles, this means you have not done a thorough job of rinsing.

    Give the coat the squeaky clean test by running your hand down the horse's wet coat.  If the feel is filmy or slippery, rinse again.

    Using a different cooler than the one you used in the middle of the bath, cover the horse until he dries.  Do not use this cooler on other horses.  This cooler should also be washed between medicated baths to minimize recurrence of the problem.