Malathion and head lice

Michael Gochfeld gochfeld at
Sun Jun 24 06:35:07 EDT 2001

I realize that head lice are not butterflies, and the use of malathion 
to treat head lice will not have an impact on butterflies (there is also 
some controversy over its efficacy for head lice). 

We use many substances as medications because they are toxic to the 
target organism. This takes into account that medications have unwanted 
and in some cases dangerous side effects. 

For example, many of the most unpleasant side effects of oral 
antibiotics stem from their impact on non-target organisms in the 

The use of malathion for head lice is itself controversial and many side 
side effects, some serious have been attributed (with varying levels of 
confidence) to its use.  It is used only for a condition that is itself 
quite serious and difficult to treat.  Its safety is only relative to 
the seriousness of the condition. 

The analogy between safety for medical use and for general application 
is not great since the attorney (Snell and Wilner) for Medicis (the 
manufacturer of Ovide) acknowledges in a letter apparently threatening 
libel action against an anti-head lice organization 

"As you clearly know, medical studies and tests have been conducted 
concerning the industrial grade use of malathion, which conclude 
inappropriate use of the pesticidal spray malathion  may have toxic 
side-effects.  The industrial grade of malathion contains many 
impurities which have been associated with reported side-effects." 

This is from the text of a letter signed Snell and Wilner. Like most 
things posted on the internet, one must use caution in believing what 
one reads. 

M. Gochfeld

Michael Gochfeld MD, PhD
Professor of Environmental and Community Medicine
UMDNJ-Robert Wood Johnson Medical School
EOHSI Building---170 Frelinghuysen Road
Piscataway, NJ 08854  USA
Phone 732-445-0123 x627   fax 732-445-0130
"gochfeld at"


   For subscription and related information about LEPS-L visit: 

More information about the Leps-l mailing list