DMSO (dimethyl sulfoxide) is a clear, odorless liquid made from wood pulp. It has been used since the 1950's as an industrial solvent. 

It was first used medically in the early 1960s. Since then, DMSO has been hailed as everything from a miracle drug to a cancer causing toxin. It has been used sporadically in human medicine. Some MDs have touted the amazing effects of DMSO, but it has never been widely accepted. DMSO is only FDA approved for human use as a tissue transplant preservative and for the treatment of one type of bladder inflammation (cystitis). It is FDA approved for horses as a topical medication.

HOW IT WORKS

DMSO has many interesting and rare properties. Most importantly, DMSO is a non-steroidal anti-inflammatory drug (NSAID), and it has a molecular structure which allows it to penetrate through skin and cell membranes into the bloodstream without causing damage.

DMSO has antioxidant properties that are considered anti-inflammatory. It is considered a powerful free radical scavenger. DMSO has some antibacterial action. It slows the multiplication of bacteria but does not kill them. DMSO may provide some short term pain relief, either through reduction in inflammation or direct pain relief.  DMSO is a diuretic, and so results in increased urine production.

VET'S ROLE

For bruises, strained muscles and soft tissue injuries, vets frequently use DMSO solution or gel topically for its direct anti-inflammatory effect and tissue penetration. DMSO can also be mixed with steroids, antibiotics and antifungals to try to get them to penetrate more deeply into the tissues to sites of injury or infection.

DMSO can be safely used topically for a number of conditions. DMSO can be used as a poultice alone, or with other medications. It draws water (swelling) out of tissues. It is often used in sweat wraps and topically to reduce swelling and pain at the injury site.

DMSO is also mixed in intravenous fluids, or mixed with water and administered orally through a stomach tube to treat these conditions:

- Treatment of brain and spinal cord injury and inflammation.  

- Treatment of horses with laminitis (hard to quantify the results). 

- Treatment in post-colic surgery endotoxemia to protect tissues from inflammation and free-radical damage.

- Treatment of arthritis, as it may help reduce inflammation and pain.

- As a diuretic, in cases where there is excessive fluid that needs to be removed from the body, such as pulmonary (lung) edema.

YOUR ROLE

Horses treated with topical DMSO need to be monitored for local irritation. Horses that have been given oral or intravenous DMSO should be watched for side effects.