Grapefruit seed extract kills strep. Whenever I start to get a sore throat I gargle with 3 drops of GSE in 4 oz of water. It tastes pretty nasty! I've given it to DD (21 months) in OJ. Just a few drops in her sippy cup. The OJ does a good job at masking up the unpleasant taste.
http://www.nutriteam.com/index2.html#strep
http://www.nutriteam.com/index2.html#strep