My wife informed me she found this ingrediant in Similasan earache relief drops. She was going to put some in my 5 year olds ear, but noticed this ingredant and stopped. There is some information on the following website.

http://www.savetonsils.com/medtons.htm#2

The following website for Similason is trying to tell us it is safe.

http://www.similasanusa.com/pdfs/mercuryinfo.pdf