In Judaism, is it "allowed" to consult a medium ?

Hello dogsbollocks-ga,

It seems clear that Judaism does not allow the consulting of mediums. 
Two of the 613 commandments specifically concern mediums, and both are
negative.  These commandments admonish not to perform "ov" (plural
"ovos" or "ovot") and not to consult the "ov".  "Ov" means "medium" in
the sense you have indicated.  (There are also negative commandments
about several similar things, such as contacting the dead and
muttering incantations.)

"613 Commandments" [see especially numbers 47 and 65]
Aish.com
http://www.aish.com/holidays/Shavuot/The_613_Commandments.asp

"Leviticus » Chapter 19" [see verse 19:31, and definition further down
the page for "mediums"]
Nagivating the Bible II [World ORT]
http://bible.ort.org/books/pentd2.asp?action=displayanchor&pentid=P3310

"Parshas Naso", by HaRav Eliezer Chrysler [under "The Mitzvos of
Today", number 170]
Shema Yisrael Torah Network
http://www.shemayisrael.co.il/parsha/chrysler/archives/nasso61.htm

- justaskscott-ga


Search terms used on Google:

judaism commandments
"19:26" "19:31" "18:10" ov medium
ovos mediums

justaskscott-ga is correct in his conclusion.

Technically, however, Ov is a very specific type of medium-consulting,
and not a general prohibition against all medium-consulting. There is
a general prohibition, but its source is Deuteronomy 18:13.

--ravuri-ga

Actually, it appears to be Deuteronomy 18:11, but perhaps that is the
better citation.

"Deuteronomy » Chapter 18" [see verse 18:10-11]
Nagivating the Bible II [World ORT]
http://bible.ort.org/books/pentd2.asp?ACTION=displaypage&BOOK=5&CHAPTER=18