Green Tea & Me!

DB Ryen

Marlie has heard all about the benefits of drinking green tea, but unfortunately it makes her feel sick. What's going on? 

[Keywords: green tea, herbals, supplements, natural treatment, caffeine, medication, doctor, medicine, physician]

Length: Short, 850 words

Dear Dr Ryen.


When I drink green tea, especially jasmine green tea, I get super jittery and my heartbeat increases and sometimes I feel a bit nauseous or have a headache. This can happen after only half a cup! Usually I feel obligated to try to finish my cup and the effects get worse by the time I'm done and lasts for some time (usually over an hour, although eating carb things like bread can help). I know these effects can happen when people drink coffee, and most coffee makes me feel this way too, even just a half cup (so I don't drink coffee). But I do drink one cup of black tea every day and that has more caffeine than green tea and I never have any weird effects! There are a couple of green teas that don't bother me as much, but generally it doesn't sit well with me.


There's a Reddit post of somebody else that feels the same way and some commenters do too, but there's no other blogs or anything that matches what my body does. The blogs all say that green tea is super healthy OR they say that high amounts of caffeine can cause these side effects. This is expected since most studies on green tea are about health benefits. There's an article from Times of India which talks about some people having adverse effects with green tea. I'm hesitant to give it much credit though since I'm pretty sure allergy symptoms are a lot different. But it's the only other thing that talks about a small group of people not boding well with green tea.


All in all, it's not really a bother because I now just don't drink green tea. But I'm curious if you've seen or heard of other people who's bodies don't like green tea. Over to you!

- Marlie, Williams Lake, BC



Great question! You've brought up a lot of different issues, so let's tackle them one at a time.


First, evaluating adverse effects from herbal supplements (i.e. non-medicines like tea) can be tricky. Just because something is "natural" doesn't mean it's safe. In fact, there are a number of nutritional supplements that can cause dangerous interactions with medications or medical conditions. It's often because there are lots of chemical compounds in these concoctions that can potentially have all sorts of effects. Also, each person, with their unique genetic signature, reacts differently. Furthermore,  just like you noticed how different brands of green tea affect you differently, each individual product has different chemical properties. That is, each company has its own unique variation of plant species and manufacturing processing, which means that two brands with the same name on the label can have vastly different chemical compositions.


In terms of the medical evidence for or against green tea, it's weak at best. Very few reputable studies exist to say definitively whether it's "good for you" or causes harm. Some researchers say green tea slightly reduces the risk of lung cancer and prostate cancer, plus slightly increasing in bone density. Caffeine, however, slightly increases the risk of some cancers. All in all, the cancer risk seems to be a wash - there's no good evidence that coffee, tea, or other forms of caffeinated drinks affect the risk of cancer. There's some evidence that high doses of green tea extracts can cause liver damage, but such reactions are uncommon and usually reversible once the product is discontinued. 


In your case, I suspect there's something in green tea that doesn't sit well with your specific biological makeup. It's not likely an allergy, but perhaps an intolerance? That term gets tossed around a lot (often misused), but many people simply don't react well to certain medications, herbals, or foods. I have a couple of patients who get headaches and diarrhea anytime they eat raw onions. Others don't like consuming gluten, even though they show no evidence of celiac disease on biopsy of their small intestine. Lots of people get nasty reactions from red wine and dark chocolate, while others think they're heavenly. I like how you have the insight to know that not everything you read on the internet is accurate. Despite blogs saying "green tea is super healthy", it's not actually healthy for you because it gives you a headache, jitters, and nausea every time you drink it. 


So, I don't have a great reason for why green tea causes you problems, but it's safe to say continuing to avoid it is probably in your best interest 


Hope that helps!

© D. B. Ryen Incorporated, February 2023.  

Disclaimer: This is not medical advice. does not assume any liability due to incorrect or complete information you might obtain here. The information on this website (and elsewhere on the internet) does not replace the personalized advice from a qualified healthcare practitioner you trust. 

A version of this article appeared online in Christian Women Living.