My dd was catching everything going when she was 7 years old because of overprescription of antibiotics on the part of the doctor, who never once showed any concern for how often she was getting sick. In desperation I took her to an acupuncturist who prescribed her some Chinese herbs and she didn't get sick for another two years.
Alternatively, your daughter at age seven ran into a number of infectious illnesses she had not encountered before and she caught them, possibly because she was a little run down or for some other reason entirely unrelated to antibiotics. Subsequently her immune system, by now working much better, and primed against those illnesses she had already experienced, kicked in, allowing her to remain well for the next two years and coincidentally occurring at the same time she received some herbal medicine which did no harm, but also had no effect.
Another alternative is that given the herbal medicine, and your obvious approval, your daughter expected to feel better, and therefore was better. It's called the placebo effect.
Your story does not prove that the medicine helped. Only that personal perception is easily fooled and that human beings tend to behave in ways that are not scientifically rational, even when they try very hard. We are hard-wired through thousands of years of evolution to place more emphasis on personal experience than we place on more scientific methods.