I only know the newer regular medical stuff from the vet's you put a dab of behind their head. My cats got an infestation 3-4 summers ago and that did the trick.

</font><blockquote><div id="quote"><font class="small">Quote:</font>
Ground pennyroyal is one of the most effective tick deterrents available

</div></font></blockquote><font class="post"> From: http://www.seedman.com/pest.htm