Intended for healthcare professionals

Feature Christmas 2018: Look Before You Leap

Adventures in self experimentation

BMJ 2018; 363 doi: (Published 11 December 2018) Cite this as: BMJ 2018;363:k5006
  1. Gareth J Parry, old research professor,
  2. Eric J Buenz, young research professor
  1. Nelson Marlborough Institute of Technology, Nelson, New Zealand
  1. eric.buenz{at}

Gareth Parry and Eric Buenz explore the storied history of scientists using themselves as guinea pigs

Self experimentation is a rich medical tradition, leading to remarkable scientific advances but also erroneous conclusions and, sometimes, death.

Recently we explored the properties of Urtica ferox, a stinging nettle endemic to New Zealand (fig 1). During a collection expedition a 71 year old emeritus neurologist indulged in inadvertent, and subsequently deliberate, self experimentation. His notes of the evolving neurological manifestations after exposure provide clues to the toxin’s mechanism of action that would be difficult to draw without self experimentation (see box 1 for notes).

Fig 1

Self experimentation by an emeritus neurologist.Urtica ferox is a tree nettle growing >2 m tall, endemic to New Zealand (A), with trichomes that contain a putative neurotoxin (B). During a collection expedition and subsequent sample preparation an emeritus neurologist exposed himself to the fluid in the trichomes (C) and recorded the experience in detail (D).

Box 1

The emeritus professor’s notes after exposure to the neurotoxic stinging nettle

Immediate, moderately severe, burning pain at the site of penetration spread over 5-10 seconds to involve an area 1 cm in diameter. The pain began to subside within five minutes and had resolved within 60 minutes. As the pain subsided paraesthesias appeared that were intense and annoying but not truly painful, and allodynia was noted in the affected area.

Paraesthesias were constant for 18 hours and then became intermittent (particularly triggered by cold) and resolved completely by 48 hours. Numbness developed within 30 minutes of onset of paraesthesias. At nadir, complete loss of cold thermal and light touch sensation was noted, and pin prick thresholds were increased, but hyperalgesia occurred when the threshold was exceeded. At 18 hours the numbness began to recede in severity and extent, and it resolved completely by 72 hours.

Urtica ferox contains several chemicals that may account …

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