My Son Is 3 Year Old And Had Urine Infection

My Son is 3 year old and had Urine infection 2 months back. We did Urine culture and it was found sensitive. Alkasol was prescribed to him and it cured. He is again facing the same problems, burning sensation, yellowish urine, small red dots all over his back. He was unable to eat anything since last 4-5 days. I gave him Alkasol and the burning sensation has reduced, red dots are gone and he is eating again. Why is it occuring so frequently? Can Alkasol alone cure this?