i used ivermectin horse worming paste to deworm/de-nastify my rats. they do make tiny syringes! and they are most helpful in administering uncooked grain of rice sized doses to rats (less than that if they aren't adults that you are dosing). i just picked up the rat, popped the syringe in its mouth and administered (you can fill up the syringe and test to see how much (how many mLs or whatever) equals the amount you want to dose with)--it's such a small amount that once in their mouth or even around their mouth they just lick and swallow. when i was deworming becky advised dosing once per day for 3 weeks--she said otherwise the effects would be minimal if any. it worked great for me!