No, they cannot be used with HRT. Both contain a substance similar to estrogen known as phytoestrogen and may cross react.
I hope this helps.
Let me know if you need more input. If not, please click on the green"Accept" button on this page. A positive rating and adding a bonus will be warmly appreciated.
If you are taking HRT and still having hot flushes, I would talk to your doctor about increasing it. Studies have shown that Black cohosh is no more effective than placebo.