Patient Education

Mast Cell Activation Syndrome

What are the diagnostic criteria, symptoms and the effects of mast cell activation syndrome?

This is a complex disorder that needs to be managed by a team which can include an allergist and gastroenterologist. Please note that Dr. Weinstock has an interest in this syndrome but owing to time schedule and other factors, will only be able to add a new MCAS patients a few at a time and the waiting list for Dr. Weinstock is long.

Major Diagnostic Criteria for MCAS:

  • Classic symptoms of mast cell activation in ≥2 organ systems (skin, cardiovascular, nose, respiratory, GI, ocular, and/or history of anaphylaxis)

Minor Diagnostic Criteria for MCAS:

  • Response to MC therapy
  • Evidence of increased MC mediators
  • Focal or disseminated increased MC in BM and/or GI tract (CD117-, tryptase-, and CD25-MC express CD2 and/or CD25)
  • Spindle-shaped morphology in >25% of MC

Consent forms:

MCAS Testimonials

I wanted to report that a few weeks into cromolyn I am feeling so much better. Much less gastro problems, more energy, less brain fog, and way less inflammation. Thanks for helping me to get on this! It's been a miracle after years of suffering. -K


Thanks so much for your help! My current mast cell cocktail is working very well, by the way and I am feeling and functioning much better these days. Thank you again for all you do!


I had a humming noise in my ears for a long time.. It stopped 2 weeks after I started the mast cell medicines. The burning smell stopped also.


DR WEINSTOCK WOW... so I was already starting to feel a bit better as I added Quercitin/D/C/Pepcid this week and changed my diet, but I started LDN 1mg in the morning on Thursday and HOLY SH*T I apologize for my language but I cannot freaking believe how much better I feel. I did not realize how bad my fatigue, muscle pain, and brain fog had gotten. I am also noticing the way some of my flare-ups are working although I cannot identify triggers yet. I wanted to thank you for putting me on this medication - oh my god. I forgot I could feel this good, Talk soon - thank you so much again for your life-changing efforts. I can't stop crying of happiness. Can't wait to keep improving!



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Frequently asked questions on polyps.

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Rosacea and SIBO connection explained


Rosacea generally occurs without an obvious explanation. In 2008, it was discovered that rosacea is associated with small intestinal bacterial overgrowth (SIBO). The lactulose breath test (see below) diagnoses the presence of SIBO.

read more about rosacea



Watch Video



Dr. Leonard Weinstock talks about Rosacea. After clicking the link, please wait a moment for the download, and the video will begin playing automatically. (You may need to disable your pop up blocker).


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Colon Cancer

Dr. Aman Singh talks about colon cancer. After clicking the link, please wait a moment for the download, and the video will begin playing automatically. (You may need to disable your pop up blocker).

FMT PowerPoint Presentation:

Anti-Inflammatory Diet

Podcasts on SIBO and healthy life style

SIBO Survivor interview with Dr. Weinstock

Dr. Weinstock interviews with SIBO Survivor.

Watch SIBO video: SIBO Causes & Co-Existing Conditions with Dr. Weinstock

Other helpful link/information: