PCT No. PCT/GB95/01894 Sec. 371 Date Jan. 29, 1997 Sec. 102(e) Date Jan. 29, 1997 PCT Filed Aug. 10, 1995 PCT Pub. No. WO96/05879 PCT Pub. Date Feb. 29, 1996A fluid handling device has a needle retraction assembly which brings about the retraction of a hollow needle after use. A hollow body portion is provided at one end, with an end wall having a mounting portion including a needle passage. A hollow needle having a leading end portion is movable between a first position in which the leading end portion of the needle protrudes from a front end portion of said mounting portion and a second position in which the needle is withdrawn within the hollow body portion. A spring acts to bias the needle into the second, withdrawn position. The needle is provided with a portion of enlarged diameter at a location spaced from the leading end portion. A retainer maintains the needle in its first position until use is completed. The retainer includes an O-ring positioned in a circumferential groove in the portion of enlarged diameter. The O-ring abuts the end of a sleeve slidable within the mounting portion and which can be forced forwardly to dislodge the O-ring so as to permit the needle to move from its first position into its second position under the influence of the spring.