In 1853, he invented the first hypodermic needle that used a true syringe and hollow needle. Wood referred to his invention as "subcutaneous" rather than "hypodermic". The term "hypodermic" was actually invented by Charles Hunter, whose developments of Wood's invention and research into the method of administering pain relief angered Wood. Wood believed that injections should be directly into the area where pain was felt, because the effect could only be local, whereas Hunter argued that the injection could be given anywhere and had a general effect. The medical community supported Hunter's hypothesis, though it is Wood who has been better remembered subsequently.
Wood's biographer and brother-in-law, the Very Reverend Thomas Brown (1811-1893), wrote that Wood had taken the sting of the bee as his model. Brown also wrote, 'At first this new hypodermic method was employed exclusively for the administration of morphia and preparations of opium, but it is important to note that, from the outset, Dr Wood pointed to a far wider application.' In referring to the preface of a paper on '"New Method of Treating Neuralgia by Subcutaneous Injection," separately published in 1855', Brown quotes Wood as saying, 'In all probability, what is true in regard to narcotics would be found to be equally true in regard to other classes of remedies.'
There is a story in circulation that Wood's wife, Rebecca Massey, was the first known intravenous morphine addict and died of an overdose delivered by her husband's invention, however, Richard Davenport-Hines says, 'It is a myth: she outlived him, and survived until 1894.'
Wood is buried with his wife, Rebecca Massey, in Dean Cemetery in Edinburgh. The grave lies on an east-facing section of the obscured southern terrace. The gravestone corroborates a later date for his wife's death, on 6 February 1895.
- "From Charles Mackintosh's waterproof to Dolly the sheep: 43 innovations Scotland has given the world". The independent. 30 December 2016.
- Brown, Thomas (1886). Alexander Wood, M.D., F.R.C.P.E.,&c.&c. : A sketch of his life and work. Macniven & Wallace. p. 203. Retrieved 18 March 2016.
- Waterston, Charles D; Macmillan Shearer, A (July 2006). Former Fellows of the Royal Society of Edinburgh 1783–2002: Biographical Index (PDF). II. Edinburgh: The Royal Society of Edinburgh. ISBN 978-0-902198-84-5. Archived from the original (PDF) on 4 October 2006. Retrieved 7 June 2011.
- Yaksh, Tony L. (1999). Spinal drug delivery. Elsevier Health Sciences. p. 15. ISBN 0-444-82901-6.
- Brunton, D. (2000). "A Question of Priority: Alexander Wood, Charles Hunter and the Hypodermic Method". Proceedings of the Royal College of Physicians of Edinburgh. 30: 349–351.
- "Some (mostly Scottish) local anaesthetic heroes" (PDF). Royal College of Physicians of Edinburgh. Retrieved 5 November 2015.
- Richard Davenport-Hines (2003). The Pursuit of Oblivion: A Global History of Narcotics. W.W. Norton. p. 68. ISBN 978-0-393-32545-4.
- Edinburgh and Leith Post Office Directory 1883-84