Cat Gut Strings. Are They Still Used for Violins?

History of Catgut Strings

The practice of using cat gut for musical instrument strings dates back to 16th century Italy. Cat gut, which refers to the dried and stretched intestinal cords of various animals like sheep, was the ideal material at the time due to its unique combination of strength, flexibility, and low density [1]. Its low elasticity meant it could provide brilliant tone and clarity when used on string instruments. The gut fiber’s spin cylindrical configuration made it sturdy yet easily shaped into strings. Cat gut quickly became the dominant material for violin, harp, lute, and other strings across Europe in the 16th-18th centuries. It remained unrivaled for centuries due to its acoustic properties until metal and synthetic alternatives emerged in the 20th century.

Modern Alternatives Emerge

In the early 20th century, violinists began experimenting with synthetic core strings as an alternative to traditional catgut strings. According to History of strings, steel and various textiles like nylon were used to create more durable and weather-resistant violin strings.

By the 1970s, synthetic core strings without any animal products became widely available and popular. Thomastik-Infeld launched the first successful synthetic strings known as Dominants, which contained a nylon core and steel winding (Pecotić, 2023). These early synthetic strings offered great tuning stability and projection compared to natural gut strings.

While synthetic strings solved many of the issues with gut strings, such as quick wear and vulnerability to humidity changes, some musicians still preferred the warmth of tone and playability of real gut. Each type of string has tradeoffs in terms of tone, response, and maintenance needs.

Catgut Today

While synthetic strings have largely replaced catgut strings, a small niche market for gut strings remains, according to Johnson String Instrument. Some violinists still prefer the tone quality of authentic gut strings, especially when performing early music on period instruments. The unique acoustic properties of gut strings produce a warm, mellow sound prized by certain players.

However, catgut strings are more delicate and sensitive to changes in temperature and humidity compared to modern materials. They require more frequent tuning and break more easily if not handled with care. These downsides make catgut impractical for most non-professional players today. Their use is now mainly limited to historically informed performances of Baroque or earlier music. While an overwhelming majority uses steel or synthetic strings, catgut maintains a dedicated following among a small niche of top artists seeking an authentic sound.

Catgut Manufacturing Process

The catgut manufacturing process is an intricate and specialized art requiring great skill and expertise. Though “catgut” strings get their name from being originally made from cat intestines, today most come from sheep or goat intestine (Wikipedia). The parts of the cat intestine used are the muscular layers known as the submucosa and serosa. These long tubular parts are extracted and cleaned.

The lengthy intestines are then split down their length into long thin strips. These strips are twisted and stretched in a process known as wet spinning. This aligns the protein fibers within the guts for optimal strength. The strings are then polished and treated to control thickness and flexibility. They may also be treated with various chemicals to control color and improve preservation. It is meticulous and painstaking work, often undertaken in specialist facilities around the world.

The highest quality catgut strings are still crafted by hand in this traditional way. It requires years of apprenticeship to master the techniques. Machines have been designed to automate parts of the process, but artisanal hand craftsmanship remains essential for the highest grade catgut strings used by professional musicians (WQXR).

Sourcing Cat Gut

Traditionally, catgut strings were actually made from the intestines of cats and other animals. However, this practice of using real cat gut has largely been discontinued. According to Wikipedia, “catgut suture material has not contained cat gut for at least 40 years.”

Most modern so-called “catgut” strings are made from the intestines of cows or sheep. The colloquial term “catgut” has been retained for historical reasons. According to the WQXR article, some small specialty string makers still claim to use real cat gut, but this is rare and controversial.

The ethical concerns around sourcing genuine cat gut have led string manufacturers to switch to cow and sheep parts. While some traditionalists argue real catgut has unique tonal qualities, the mainstream industry view is that the differences are negligible and not worth the ethical costs of using cats.

Cost and Availability

Catgut strings are much more expensive than synthetic strings. A set can cost $300 or more compared to $20-50 for common synthetic brands like Dominant and Evah Pirazzi (Plain Gut Strings). This is due to limited production and higher manufacturing costs.

Only a handful of specialty luthiers and small workshops still produce catgut strings today. Major string manufacturers like Pirastro have discontinued catgut production in favor of more affordable and consistent synthetics. Countries like Italy, Germany, and France are among the few still manufacturing small batches of premium catgut (PIRASTRO PASSIONE Violin String).

The overall supply is quite limited globally. Catgut strings can be difficult to source and may require a long wait time. This restricts availability further compared to readily available synthetic brands.

Tone of Catgut Strings

Catgut strings are known for their warm, organic sound which is preferred by some violinists. The natural gut material resonates differently than modern synthetic cores, producing a complex tone rich in overtones. As cellist Steven Isserlis describes it, “the sound of a gut string seems to come from deep inside the instrument” (Source).

Compared to steel strings, gut has more tonal nuance and quick transient response. The sound is described as mellow and golden in the lower registers, and silvery and singing up high. There is a natural variability to gut strings, with more complexity revealed the more the instrument is played. The tone evolves over the lifetime of the string.

Hearing catgut strings in action best demonstrates their unique sound. Violinist Rachel Barton Pine is a prominent gut string performer, and her albums showcase the rich, emotive sound catgut lends to the instrument. On her Bach album Violin Lullabies, the warmth of the gut strings pairs beautifully with the violin’s woody timbre for an intimate, heartfelt recording.


Catgut strings require more delicate care and maintenance than modern strings made with synthetic materials like nylon or steel. As natural products, catgut strings have a much shorter lifespan and can be affected by humidity and temperature changes.

Players using catgut need to handle the strings very carefully to avoid damaging them. The material is more fragile than steel or synthetic cores, and even small nicks or scratches can impact tone and playability. Violinists report catgut strings lasting weeks or months rather than years like other materials.

Humidity is especially important for catgut strings. Too much humidity causes the strings to slacken as the material absorbs moisture, while very dry conditions make the strings brittle. Maintaining an ideal humidity range between 40-60% is recommended. Players may need to loosen or tighten the strings to compensate for humidity swings.

With their delicate nature and shorter usable lifespan, catgut strings require more vigilance and care from musicians. But for those seeking a warm, organic tone, the extra effort can be worthwhile.1

Future Outlook

Catgut strings are likely to remain a niche product used mainly by professional musicians who play period instruments or seek an authentic historical tone. Catgut is not widely used by student violinists due to the higher cost and specialized needs of gut strings.

The period instrument community is invested in preserving the use of catgut strings in historically informed performances. As long as there is interest in recreating the sound of Baroque, Classical, and early Romantic era stringed instruments, there will remain a market for catgut strings. However, most mainstream and amateur musicians will continue to opt for less expensive and more stable synthetic or steel options.

A few specialty string makers are keeping the traditional methods of catgut string manufacturing alive. While mass production is unlikely, this cottage industry serves the small but dedicated market of musicians who seek the authentic tone and playing experience of catgut strings.


While catgut was once the primary source of strings for violins and other musical instruments, today most manufacturers use synthetic materials like nylon and steel. The process of sourcing, cleaning, and processing cat intestines into strings is costly and time-consuming. As a result, true catgut strings are now quite rare.

However, some professional musicians and luthiers still prefer the warm, organic tone of catgut over modern synthetic strings. The natural gut resonates beautifully and produces a rich complexity of overtones. For certain instruments like the baroque violin, catgut strings are also historically accurate.

Though limited in availability today, traditional handmade catgut strings can still be sourced by a few specialty string makers around the world. While the majority of violinists opt for easier to obtain and maintain steel or synthetic strings, catgut remains an important part of the instrument’s centuries-old history and tradition.

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