A scalpel is a small and extremely sharp bladed instrument used for surgery, anatomical dissection, and various arts and crafts. Scalpels may be disposable or re-usable, re-usable scalpels can have attached, resharpenable blades or, more commonly, non-attached, replaceable blades. Disposable scalpels usually have a plastic handle with an extensible blade (like a utility knife) and are used once, then the entire instrument discarded. Double-edged scalpels are refereed to as "lancets".

Scalpel blades are usually of hardened and tempered steel. Medical blades are made of 440C stainless steel, while craft blades can be made of high carbon steel; in addition, titanium, ceramic, diamond and even obsidian knives are not uncommon. For example, when performing surgery under MRI guidance, steel blades are unusable (the blades would be drawn to the magnets) or may cause image artifacts. Alternatives to scalpels in surgical applications include electrocautery and lasers.

Surgical scalpels consist of two parts, a blade and a handle. The handles are reusable, with the blades being replaceable. In medical applications, each blade is only used once (even if just for a single, small cut). Medical scalpel handles come in two basic types. The first is a flat handle used in the #3 and #4 handles. The #7 handle is more like a long writing pen, rounded at the front and flat at the back. A #4 handle is larger than a #3, and while some blades fit both others are too large or small and can only fit one or the other. The following table of blades is incomplete and some blades listed may work with handles not specified here.

Also called the "dinner knife" grip. The handle is held with the second through fourth fingers and secured along the base of the thumb, with the index finger extended along the top rear of the blade and the thumb along the side of the handle. This grip is best for initial incisions and larger cuts.

Best used for more precise cuts with smaller blades (e.g. #15) and the #7 handle. The scalpel is held with the tips of the first and second fingers and the tip of the thumb with the handle resting on the fleshy base of the index finger and thumb. Care should be taken not to allow the handle to rest too far along the index finger as this promotes an unstable grip and cramped fingers. This is widely considered the non-standard grip by the medical professionals, despite its more practical usage.

Graphical and model-making scalpels tend to have round handles, with textured grips (either knurled metal or soft plastic). These are often called by the name of the most well-known manufacturer of graphic arts blades, X-Acto knives. The blade is usually flat and straight, allowing it to be run easily against a straightedge to produce straight cuts.

There are many kinds of graphic arts blades, the most common around the graphic design studio is the #11 blade which is very similar to a #11 surgical blade (q.v.). Other blade shapes are used for wood carving, cutting leather and heavy fabric, etc.

In the last decade, a rising awareness of the dangers of sharps in a medical environment has led to the development of various methods of protecting healthcare workers from accidental cuts and puncture wounds. According to the Centers for Disease Control and Prevention, as many as 1,000 people each day are subject to accidental needle sticks and lacerations while providing medical care. Scalpel blade injuries are among the most frequent sharps injuries, second only to needlesticks. Scalpel injuries make up 7 percent to 8 percent of all sharps injuries.^{[1] [2]}

"Scalpel Safety" is a term coined to inform users that there are choices available to them to ensure their protection from this common sharps injury.^[3]

Safety Scalpels are becoming increasingly popular as their prices come down and also on account of legislation such as the Needle Stick Prevention Act. There are essentially two kinds of disposable safety scalpels offered by various manufacturers. They can be either classified as retractable blade or retractable sheath type. The retractable blade version made by companies such as DeRoyal, Jai Surgicals, Swann Morton are more intuitive to use due to their similarities to a standard box-cutter. On the other hand, retractable blade versions are not as precise because the blade tends to wobble. Retractable sheath versions made by companies such as Aditya Dispomed, Becton Dickinson and Personna offer greater stability, ergonomic feel, strength and balance. Few Companies have also started to offer a safety scalpel with a reusable metal handle. In such models, the blade is usually protected in a cartridge. Such systems usually require a custom handle and the price of blades and cartridges is considerably more than for conventional surgical blades.

However, CDC studies shows that up to 87% of active medical devices are not activated. Safety scalpels are active devices and therefore the risk of not activating is still significant. ^[4] There is a study that indicated there were actually four times more injuries with safety scalpels than reusable scalpels.^[5]

There are various scalpel blade removers on the market that allows users to safety remove blades from the handle, instead of dangerously using fingers or forceps. In the medical field, when taking into account activation rates, the combination of a single-handed scalpel blade remover with a passing tray or a neutral zone was as safe and up to five times safer than a safety scalpel.^[6] Companies like Qlicksmart offers a single-handed scalpel blade remover that complies with regulatory requirements such as US OSHA Standards.^[7]

The usage of both safety scalpels and a single-handed blade remover combined with a hands-free passing technique are potentially effective in reducing scalpel blade injuries. ^[6] It is up to employers and scalpel users to consider and use safer and more effective scalpel safety measures when feasible.