top of page


PhytoMast® is a plant-based formula successfully used by hundreds of veterinarians and farmers across the US, Canada and around the world on thousands of animals. And while it is fairly simple to use, we want to make sure you get the best results from using PhytoMast® by answering a few common questions. If you have any questions not covered here, feel free to contact us. If you need further in-depth advice on your specific situation, Dr. Karreman is also available for paid consultations.



  • Thymol is a well-known compound and its use in veterinary medicine is found in many textbooks and product catalogues dating back to 1900. 

  • Thymol has been used primarily as a disinfectant due to its antibacterial properties. Thymol has also been included in veterinary formulas against parasitism (internal and external), fungal skin infections, upper respiratory issues and dental needs.

  • Thymol is an active ingredient in the Haver-Glover product of 1928 sold for cows and called “H-G Intramammary Disinfectant” (A Manual Of Veterinary Therapeutics. Haver-Glover Laboratories, Kansas City, MO 1928, pg. 98). On this basis, PhytoMast with Thymol is presented for drying-off cows.

  • Thymol is considered GRAS (Generally Recognized As Safe).

  • PhytoMast with its active ingredient of thymol has had its pharmacokinetics, milk and meat residues, in-vitro efficacy, and clinical efficacy for dairy cows and goats written up in 8 peer-reviewed journal publications (including the Journal of Dairy Science) and studied in-depth for a successful PHD.

  • PhytoMast is a phytoceutical (type of plant medicine). Because of the multitude of biochemicals in any plant, there is a near zero chance of antibiotic resistance. Not culturing milk and checking for appropriate antibiotic selection and then continually using the same antibiotic to dry-off cows goes against basic medical principles and leads to antibiotic resistance. 

  • PhytoMast does NOT trigger the Delvotest P nor Charm SL Beta-lactam tests, which are commonly used to check for antibiotic residues.

  • PhytoMast is manufactured and packaged in the USA. (Many products for dry-off are manufactured in India and China.)

  • PhytoMast is OMRI approved.

bottom of page