Wireless capsule endoscopy (WCE) is a powerful tool for medical screening and diagnosis, where a small capsule is swallowed and moved by means of natural peristalsis and gravity through the human gastrointestinal (GI) tract. The camera‐integrated capsule allows for visualization of the small intestine, a region which was previously inaccessible to classical flexible endoscopy. As a diagnostic tool, it allows to localize the sources of bleedings in the middle part of the gastrointestinal tract and to identify diseases, such as inflammatory bowel disease (Crohn's disease), polyposis syndrome, and tumors. The screening and diagnostic efficacy of the WCE, especially in the stomach region, is hampered by a variety of technical challenges like the lack of active capsular position and orientation control. Therapeutic functionality is absent in most commercial capsules, due to constraints in capsular volume and energy storage. The possibility of using body‐exogenous magnetic fields to guide, orient, power, and operate the capsule and its mechanisms has led to increasing research in Magnetically Guided Capsule Endoscopy (MGCE). This work shortly reviews the history and state‐of‐art in WCE technology. It highlights the magnetic technologies for advancing diagnostic and therapeutic functionalities of WCE. Not restricting itself to the GI tract, the review further investigates the technological developments in magnetically guided microrobots that can navigate through the various air‐ and fluid‐filled lumina and cavities in the body for minimally invasive medicine.

This review of the current state of magnetocalorics is focused on materials exhibiting a giant magnetocaloric response near room temperature. To be economically viable for industrial applications and mass production, materials should have desired useful properties at a reasonable cost and should be safe for humans and the environment during manufacturing, handling, operational use, and after disposal. The discovery of novel materials is followed by a gradual improvement of properties by compositional adjustment and thermal or mechanical treatment. Consequently, with time, good materials become inferior to the best. There are several known classes of inexpensive materials with a giant magnetocaloric effect, and the search continues.

The current boom of research activity in magnetocaloric materials science is fuelled by the expectation that new advanced refrigerants may be found whose ΔT will significantly surpass that of gadolinium (Gd) metal (2.6–2.9 K/T). Because of this expectation, the main effort in the field has been diverted from the important issues of refrigerator design to the routine characterization of magnetic materials. Estimating the maximum adiabatic temperature change that can be achieved in principle by applying a certain magnetic field, say 1 T, is a matter of priority. In this work the problem of maximum ΔT is approached from general principles. According to the most optimistic estimates, ΔT can never exceed ∼18 K/T, the more realistic upper limit lying somewhere in high single figures. We therefore deem it most unlikely that a refrigerant much better than Gd, in respect of the ΔT value, will ever be found.