These are some of the links we found to have the best information about porphyria:

American Porphyria Foundation A good source of information. This site has online newsletters, discusses available treatment options, and hosts group telephone conference calls with specialists (for members). Well worth a visit.

Canadian Association for Porphyria
A good resource on Porphyria, the Canadian Association promotes counselling, information, and group support programs.

Porphyria Association Inc. (Australia)
A voluntary non-profit organisation, they have basic information about porphyria and website links to safe/unsafe drug lists for porphyria patients.  See this link for the Drug Database for Acute Porphyria.

Medline Plus on Porphyria This site is sponsored by the US National Library of Medicine and the National Institutes of Health. It contains reliable information about porphyria.

“Porphyria” at the National Digestive Diseases Information Clearinghouse (NDDIC)
A USA site sponsored by the National Institutes of Health. It contains reliable information about porphyria.

New Zealand medical perspectives

Clinical indications for the investigation of porphyria: case examples and evolving laboratory approaches to its diagnosis in New Zealand.  By C. Sies, C. Florkowski, P. George, and H. Potter.  New Zealand Medical Journal, 16 Sept 2005, vol. 118, no. 1222  – Page 41 (This article is available for free online and provides explanation of the various types of porphyria.)