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A paraffin bath is a heated tub of liquid paraffin wax in which a person’s hands, fingers or feet are placed to relieve pain and stiffness. In the United States it is a regulated medical device with its own FDA classification. This page covers what the device is, how it is built, what one manufacturer’s manual specifies, how it is used and maintained, and the mistakes the manual warns against.
This page describes products and general use; it is not medical advice.
What is a paraffin bath?
The FDA defines a paraffin bath in 21 CFR 890.5110 as “a device intended for medical purposes that consists of a tub to be filled with liquid paraffin (wax) and maintained at an elevated temperature in which the patient’s appendages (e.g., hands or fingers) are placed to relieve pain and stiffness.” The same section classifies it as Class II (special controls) and exempts it from the premarket notification procedures in subpart E of part 807, subject to the limitations in 21 CFR 890.9 (eCFR, checked 2026-10-29).
Where it fits: the manual covered below describes treatment of the hands and feet and use before therapeutic exercise or massage. For the wider supply picture of a therapy clinic, see the physical therapy clinic supply checklist; for the regulatory category, see what a medical device is.
How a paraffin bath is built and how it works
The FDA definition describes two parts: a tub that holds the wax, and a way of keeping the wax at an elevated temperature. The Therabath operator’s manual (manufacturer WR Medical, models TB5 and TB4, literature CMR105, rev. 11/12/08) describes an electrically powered unit with a metal tank and a plastic grate on the bottom of the tank. The wax is melted in the unit, which the manual says takes 8 to 10 hours from solid, and then held in its working range. The manual describes treatment as covering the hand or foot with a plastic liner and placing it in the liquid wax; liners are discarded after treatment.
The manual states the purpose as symptomatic relief of pain from medically diagnosed arthritis, bursitis and chronic joint inflammation, and it also lists post-fracture or post-dislocation care, sprains, strains, restricted motion from scar tissue, and use before therapeutic exercise or massage.
Types and variants
| Variant | Typical use | Key difference |
|---|---|---|
| Therabath TB5 | Paraffin bath for hands or feet | 100-125 V supply |
| Therabath TB4 | Same product, export voltage | 220-240 V supply |
Source: Therabath operator’s manual v6.0 (Lit. #CMR105, rev. 11/12/08). These two rows are the models that manual covers; other makers and models set their own temperature ranges and capacities, so always work from the instructions for use (IFU) of the specific unit.
Specifications that matter
| Specification | Therabath TB5 / TB4 manual |
|---|---|
| Operating temperature | 126-134 F (52.2-56.7 C) |
| Capacity | 6 lbs (2.72 kg) of paraffin |
| Melt time | 8-10 hours |
| Cleaning interval | After every 40 treatments, or sooner if the wax is no longer clear or sediment builds up |
These values come from one 2008 manual for those models and are not universal figures for every paraffin bath. Follow the IFU of the unit in front of you rather than a number from another source.
How to choose
Neither the FDA definition nor the manual states buying criteria, so this page does not rank units. What the sources do establish is what to check on any unit: the supply voltage the unit is rated for (the manual lists separate 100-125 V and 220-240 V models), its stated operating temperature range and capacity, and which wax the maker permits. The manual says to use only the manufacturer’s own brand of paraffin in that unit, and that the wax must be formulated for paraffin warmers, with neither a higher nor a lower melting point than specified.
Safe use and handling basics
From the manufacturer’s manual, in general terms:
- Do not use the unit while bathing, and do not place it where it could fall into a tub or sink. If it falls into water, unplug it first and do not reach for it.
- Do not operate the unit without the plastic grate on the bottom, and do not touch the metal sides or bottom of the tank.
- Do not heat paraffin on a stove, hotplate or in a microwave, and do not add unapproved additives or pour liquids into the unit.
- Do not use it near flammable anesthetics, oxygen or nitrous oxide.
- Do not operate a damaged unit or one that is not working properly; use only accessories the manufacturer recommends and a grounded outlet that meets local codes.
- Use it on a level, secure surface and supervise use by or near children or people with disabilities.
When the manual says not to use it
The manual lists contraindications including open cuts or wounds, inflamed skin, growths, areas with impaired circulation, acute inflammation, and areas with reduced or absent sensation (for example in some people with diabetes), and says to stop if paraffin dermatitis occurs or the wax feels too hot or too cool. Whether a person can use a paraffin bath is a decision for their physician or physical therapist, not for a supplier or a web page.
Maintenance and consumables
The wax, plastic liners and the cleaning cycle are the recurring items. Per the manual: liners are optional, sold separately and discarded after treatment; the unit is cleaned after every 40 treatments or sooner when the wax is cloudy or has sediment; and abrasive powders should not be used for cleaning. The manual’s wax guidance is to use only the brand it names for that unit. Because wax and liners are consumed while the tub is not, a clinic’s supply list treats them as separate lines from the device itself.
How to use a paraffin bath
At a general level, and always subject to the unit’s IFU and a clinician’s direction: the wax is fully melted and brought to the unit’s stated operating range; the hand or foot is covered with a plastic liner as the manual describes, placed in the wax, and then removed and treated according to the clinician’s protocol. This page does not give a treatment protocol, durations or step-by-step clinical instructions, because those belong to the IFU and the treating clinician.
Common mistakes
- Treating one manufacturer’s temperature range as a universal figure.
- Running the unit without the grate, or substituting a different brand or melting point of wax.
- Skipping the cleaning cycle when the wax is cloudy or has sediment.
- Heating wax on a stove, hotplate or in a microwave instead of in the unit.
- Using the device on areas with open wounds, inflamed skin or reduced sensation.
Frequently asked questions
What is a paraffin bath used for?
The FDA’s definition says it is used to relieve pain and stiffness in a person’s hands or fingers or other appendages. The Therabath manual names diagnosed arthritis, bursitis and chronic joint inflammation, plus several rehabilitation uses.
How do you use a paraffin bath?
The limb is covered with a liner and placed in the heated wax, following the unit’s instructions and a clinician’s protocol. See the section above for the general outline and the safety points.
What temperature does a paraffin bath run at?
It depends on the unit. The Therabath TB5/TB4 manual gives 126-134 F (52.2-56.7 C); other models state their own ranges in their IFU.
Is a paraffin bath a regulated medical device?
Yes. 21 CFR 890.5110 identifies it and classifies it as Class II (special controls), exempt from premarket notification subject to the limitations in 21 CFR 890.9. See also the Medical Device Amendments of 1976 for the origin of the classification system.
Sources
- U.S. FDA, 21 CFR 890.5110 Paraffin bath: eCFR, checked 2026-10-29.
- WR Medical Electronics, Therabath Paraffin Bath operator’s manual v6.0, models TB5 and TB4, Lit. #CMR105, rev. 11/12/08, copy at manualzilla.com, checked 2026-10-29. A 2008 manual for those models only.
Related reading: physical therapy and rehabilitation research and medical thermometers.
