There have been a number of postings re. this wild flower.  Is the latin
Hypericum perforatum?  If it is, then the following info from 2 German
sources would apply.  (Sorry if this is a repeat!)::: During the time one
takes takes this herb internally, one should avoid the sun and solarium
visits, because skin reactions similiar to sun burns can occur.  People
most at risk are light sensitive people.  But the oil from this plant is
good externally for burns, and sunburns, injuries and intestinal
complaints.

Hope that applies!  (or am I burned?)
Anne Kaeser, IBCLC in Germany