Spelling bee again. An easy one, but new to me. Here's an interesting URL about it:
Since soap is a very basic medical agent, I put the post here.

MexSp < Nahuatl a:molli, lit., soap-root6
1 the root of any of various plants of the SW U.S. and Mexico, used as a substitute for soap
2 any of these plants, esp. the soap plant

As an anecdote about soap. In one of the Medical buildings at Boston City Hospital, one of
the elevator operators (the building was ancient) was a political appointee who could not
be offended without peril because of his connections, in spite of his being Italian. So there
was no use complaining about his having long range BO. But an ingenious resident was equal
to the challenge. He pretended first to be alarmed, and the pretended to try to hide his concern.
"Why you looka me like dat?" said the operator. "Don't you know you have a serious skin
condition that might turn into cancer?" asked the resident. He proceeded to write out an
elaborate prescription for Sapo mollis, applied liberally to whole body and removed by shower
daily times seven and once a week thereafter.