From the Holy Grail (qv) to Pandora’s Box. Pandora’s Box has mutated. When Pandora opened her box, the evils flew out and could not be put back in. All that remained when she closed the lid was Hope. But the dictionary definition (COD) is “a process that once begun generates many complicated problems.” A good example is incidental findings when imaging. A group from the Mayo Clinic reported incidental findings in 285 of 424 consecutive patients undergoing CT angiography for possible aortic valve replacement. What do you do then? The group sensibly concluded that we need to know more before we do more investigations, but blot their copy book in my eyes by first using the abbreviation IFs to mean incidental findings and then PPIFs to mean potentially pathological incidental findings. There is never need to use that sort of non-standard abbreviation.

Pandora’s Box could rightly be applied to many medical procedures that have ethical implications. Once you have developed in-vitro fertilisation (IVF—a standard abbreviation), who should benefit? Is it fair that heterosexual couples receive IVF from the state, but not single women? Once IVF is available, those questions will not go away: Pandora’s Box has been opened. This bears some relation to the slippery slope, a metaphor that is a logical fallacy, grossly overused, and possibly originally referring to the difficulty of getting uphill rather than the peril of sliding down.

But there are many articles in which Pandora’s Box just seems to mean that an answer has been found but it isn’t simple. In a review of antioxidants, the author described the many conflicting possibilities for good and for ill as a Pandora’s Box. The metaphor was similarly applied in a description of a protein active in autophagy, which could have therapeutic applications but with possible harms. In another article, it was applied to the psychological difficulties of supporting one’s spouse during a complex form of transplantation. The mitochondria have been described as a “cellular Pandora’s box” and great promise ascribed to the use of genetics to identify “keys to unlock Pandora’s box”: but all that flew out of Pandora’s Box were evils and—latterly—complications.

Looking at PubMed, and I suspect in general writing as well, opening Pandora’s Box has altered its meaning, and now means fiendishly complicated, or just having unknown consequences, without the overtone that it would be better left locked.

Often, a better metaphor would be double-edged sword: something that has advantages and disadvantages. Thus reactive oxygen species may be effective against certain cancers, but they can also initiate oncogenesis. Judging the needs of healthcare on the large scale collection of data has risks for the security of personal information. Double-edged sword is a good, easily understood, metaphor. Pandora’s Box is just a can of worms.

Neville Goodman is a retired consultant anaesthetist and a writer, and co-author of a book on medical English.

Competing interests: I have read and understood BMJ policy on declaration of interests and declare that my only competing interest is my co-authorship of a book about medical English.