X Chromosome

Not to stir up a battle of the sexes, but the X chromosome (females have two of them, while males have one) is five times larger than the Y chromosome, and has 10 times the number of genes. That means it carries more traits — and diseases — than the Y chromosome - Pfizer

X-ray Radiation

So, x-rays are electromagnetic radiation just like the light around us but with much higher energy - Brian Nett PhD

X-rays

It is easy and accurate to refer to an X-ray as a plain film, plain radiograph conventional X-ray, routine X-ray etc, however, these terms, understate the skill and the value of that image and what the image can reveal - Helene Pavlov MD

Xanax (Alprazolam)

The crack [cocaine] of the benzodiazepines - Andrea Tone

Xenon Anesthesia

The ‘noble’ gas xenon possesses numerous salubrious qualities which are currently underutilized in the world of clinical medicine; most notably in the field of anaesthesia - Robert D. Sanders

Xenotransplantation

Xenotransplantation — putting animal organs into humans — is a centuries’ old idea that has been revived at multiple times throughout history as technological advances offer new hope of overcoming what has seemed like a never-ending parade of scientific hurdles - Megan Molteni

Xerostomia

Once considered an inevitable part of the aging process, xerostomia is now associated with hundreds of medications and numerous nonpharmacologic conditions, including some cancer treatment regimens - Diana Lamoreux

Xofluza (Baloxavir)

In terms of symptom relief, there isn’t much difference. In the clinical trials of adults and adolescents, Xofluza alleviated symptoms about as quickly as Tamiflu. But the latter drug requires a bigger commitment from a patient: a twice-daily dose for five days, compared with Xofluza’s one dose - Aimee Cunningham

Xopenex (Levalbuterol)

The notion of a therapeutic advantage of levalbuterol over albuterol has been the subject of much controversy - Han Na Kim

XX Chromosome

Women’s bodies are capable of inactivating one of their two X chromosomes within each cell. Without this ability, XX women might not survive - Laura Freeman

XY Chromosome

It just isn't having an X and a Y chromosome that makes a male (or that having two X's makes you a female). It is what our cells do with these chromosomes that makes an embryo develop as male or female - Jessica Profato

Xylazine

The drug exists in a legal gray zone. Approved 50 years ago by the F.D.A. as a veterinarian-prescribed analgesic, it is not listed as a controlled substance for animals or humans and so is not subject to strict monitoring. Thus, it has not been on the radar of federal law enforcement for diversion or abuse - Jan Hoffman

Xylitol

Xylitol is truly the darling of sugar substitutes today. The American Dietetic Association touts its use, with this sugar alcohol sold alone and as a sweetener in a variety of processed foods - Sarah Pope