Is there a medicine that can be taken to untie tubes naturally?

Probably not: If Fallopian tubes were surgically "tied", ligated, cut, clipped or electrocoagulated...there is no "medicine that can be taken to untie them". If tubes became occluded and terribly scarred because of chronic infections, endometriosis or other inflammatory conditions, it is very unlikely that any medical treatment would "untie"them. Antibiotics and/or hormonal treatments may free mild occlusions

Can ask Gyn for help: Getting "tubes tied" (tubal ligation) is PERMANENT, and done for women who will never want to get pregnant again in the future (meaning a permanent decision of no more pregnancies, forever). Tubes are not meant to be untied. One cannot "naturally" tie tubes, nor "naturally" untie tubes, because tying tubes is not natural, but rather a surgical procedure that interferes with natural reproduction.