What are the 26 sacred herbs used by traditional Breton herbalists
(Louzaouerien)? This concept was mentioned by Alexei Kondratiev in his
book 'The Apple Branch: A Path to Celtic Ritual'(The Collins Press,
1998)although he did not name the individual herbs. I need a good
academic answer, no new-age nonsense please.

Possibly this book might have some further information:
Magie, médecine et divination chez les Celtes
Christian-J. Guyonvarc'h (The author was formerly Professor of Celtic
at the University of Rennes)
1997, Payot; (Bibliothèque scientifique Payot) ; ISBN : 2228891126 
Available for c. 25 euros on Amazon France
http://www.amazon.fr/exec/obidos/ASIN/2228891126/qid=1044360109/sr=1-1/ref=sr_1_0_1/402-8948162-2298548

Thanks. I already knew about this book, but was having trouble finding a copy of it.

Here is some further information for researchers. Breton citizens are
from Bretagne (Brittany - NW France) and not Cape Breton (Canada).
Brittany is the only Celtic country still in existance on mainland
Europe. Its folk traditions were enriched by Irish nobles (fellow
Celts) who settled there after fleeing persecution from the English.
The people of Brittany may speak either Breton or French. If you find
an answer to my question in French, I can have it translated. Thanks
and good luck!