I mostly use it externally, these days.
I got a question in my email: "I am a student of [deletia] studying Meadowsweet. Would it be possible to have some of your information on this lovely herb?"
It's a lovely herb, for sure; I pick the flowering tops, the flowerbuds, and the leaf, in order of preference, and use the dried herb in teas, oils and salves.
I use it mainly as a painkiller externally in salves; for that, it's absolutely fabulous, and it doesn't matter if the pain is self-inflicted (achy muscles, or trauma) or from some chronical problem (rheumatism, arthritis, and the like).
My salve blend with meadowsweet (dried flowers or leaf) + calendula (dried flowers) + hypericum (fresh flowering tops) was all the rage at a local hospital for people with neurological problems; they put it onto the inflamed cuticles of spastics. I'm told that spastics tend to get cuticle inflammations rather a lot.
Instead of having to give antibiotics for a week (with upset gut, with MORE spasticity for the afflicted), the salve solved the problem within 48 hours, every time.
Alas, internal use. See, long long long ago I made a tea and left it to steep for way too long -- and still drank that tea. Since then, the taste isn't "mmm, nice" but "yuk, soapy". And I find that I'm reluctant to give herbs which I don't like the taste of to clients ...
Chris Hedley uses it for stomach ulcers (along with other herbs), and the times I've given it for that (as a tea), it's worked nicely (with other herbs: a gentle astringent like Epilobium, a mucilaginous herb like mallow leaf, a gentle healer like Plantago or Calendula, plus possibly also Hypericum, just because). (That's a tea blend; take 1 teaspoon to ½ cup of boiling water, let steep 5-10 minutes, drink 2-3 teacups a day for a few weeks).
It's a sweater (= diaphoretic) for the flu and things, but people don't generally come to me with the flu - and as I really don't like the taste myself anymore, I haven't tried it on family either. Instead, I use yarrow.