I am not trying to go against the question here, but if he is getting this often, you might seriously consider getting his tonsils out. My dd got strep once in July, and by January had had it 8 times, often getting complications of bronchitis and sinus/ear infections. That January she had all four at the same time. She kept getting strep so we had to get them out, took us months to get her well enough long enough to do it. It was a very scary time for us.
To second Bookworm: Be careful with it. It can go to a person's heart and other organs quickly and do very serious damage. My point of telling this is not to freak you out, but it can and does harbor itself away! Our ENT specialist said that the strep bacteria can linger in the tonsils and continue to grow, making the tonsils swell up (getting the adnoids as well) and a child can suffocate or choke to death if not treated...with each round of strep the tonsils are usually larger anyway since they try to out-build the infection. Since my dd's have come out, she hasn't had strep once. I'd rather have them out then worry constantly about her and be on the antibiotics so much. She devoloped allergic reactions to 2 of the 5 major antibiotic families during this time. It is serious stuff.
In the meantime, make sure he is getting some really good probiotics to help heal and replace the good bacteria that helps kill the yucky ones. I am not against natural remedies, but this is one bug I am very very cautious with.