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Extensive blood and tissue samples were examined. No outward toxic signs were shown. No significant
changes were noted during or following repeated exposure. We suggest, as a good hygiene practice, avoid-
ing exposure to DMSO sprays or mists and very high doses of DMSO vapors.

Effects on Other Organisms

1. Effects on Plants. DMSO by itself and DMSO with antibiotics, minerals, nutrients, pesticides and other
materials have been sprayed on, injected into, painted on, and fed to a variety of plants. It has a low order
of phyto-toxicity in these applications.

2. Effects on Fish. Wilford

(11)

investigated the toxicity of DMSO in water to 9 species of fish. At 96 hours,

the LC-50 was 32,000 to 43,000 ppm DMSO (3-4%). This is far less toxic than acetone (fingernail polish re-
mover) and other widely used solvents.

3. Effects on Sewage Plants.
DMSO is biodegradable in biological systems, it is converted in part to methyl sulfone and to dimethyl sul-
fide. The sulfone is stable and inert and degraded only slowly by microorganisms or physical factors. At high
concentrations, some DMS may escape, producing its characteristic odor.

Natural Occurrences in Food.
The occurrence of DMSO and its metabolites, dimethyl sulfide and methyl sulfone (DMSO

), have been

widely reported in a variety of foods. Pearson

(9)

and coworkers reported finding 0.07 to 16 ppm DMSO,

along with DMSO

, in 14 fruits, vegetables or beverages. This natural occurrence insures that the body can

dispose of DMSO by well-established metabolic processes. Naturally-occurring DMSO has been identified in
alfalfa, asparagus, barley, beans, beets, cabbage, corn, cucumbers, oats, onions, Swiss chard, tomatoes,
apples, raspberries, spearmint, beer, milk, coffee and tea. DMSO concentrations in fresh fruits, vegetables
and grains ranged from undetectable (<0.05 parts per million) to 1.8 ppm.

Genotoxicity

DMSO is not mutagenic to Salmonella, Drosophila, and fish cell cultures. Because DMSO is so non-reactive as
a mutagen, it is widely used as a solvent in mutagenicity testing. Although DMSO is bacteriostatic or bactericidal
at concentrations of 5-50%, there is no evidence that DMSO causes chromosomal aberrations at levels that are
not directly toxic to cells. Bone marrow smears from primates (rhesus monkeys) that received oral or topical
doses of DMSO for 18 months showed no DMSO effects (Vogin et al., 1970)

(12)

. An in vivo cytogenetics study

of DMSO administered by intraperitoneal injection to male rats found a significant increase in aberrant femoral bone
marrow cells when compared to controls (Kapp and Eventoff, 1980)

(13)

. However, evidence from the Salmo-

nella studies and other toxicology data, especially the teratology data, suggests that the increase in aberrant
femoral cells likely resulted from direct toxicity of DMSO injected into an animal instead of a classic
"mutagenic" response.

According to Brayton (1986), there are no documented adverse genetic effects reported as a result of medici-
nal DMSO uses (including quasi-medicinal uses for treatment of arthritis or sprains and strains). Additionally, no
adverse genetic effects have been reported from occupational exposure to DMSO in over 40 years of industrial