YOUR favourite spooky treat might be harbouring an unwanted trick, an expert has warned.
Some ingredients lurking in your bucket of Halloween goodies can stop life-saving medicines from working properly.
"It's important to be aware of potential health risks associated with certain treats, especially if you take certain medications," Kiran Jones, Clinical Pharmacist at , warned.
Some drug and sweet combinations can even result in panic attacks and strokes.
It's important to read through your medicine leaflet before starting a new drug to check for any foods you're advised not to eat.
Here are four foods you should never mix with specific medicines to avoid unpleasant - and even life-threatening - complications.
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1. Sugar-free treats
Don't mix well with: Depression, anxiety and Parkinson's medicines
In an age where sugar is demonised, we often think of sugar-free alternatives as the healthier option for guilt-free sweetness.
From sugar-free gummies to zero-sugar bubble gum and artificially-sweetened fizzy drinks, there's no shortage of 'better' options.
Many contain aspartame, a low-calorie, artificial sweetener that's known for being 180 to 200 times sweeter than sugar.
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But for those taking monoamine oxidase inhibitors (MAOIs) for depression, anxiety, or Parkinson's disease, these sweeteners can pose serious problems.
"Aspartame contains phenylalanine, which, when broken down in the body, affects neurotransmitter levels," Kiran said.
"MAOIs work by preventing the breakdown of neurotransmitters like dopamine, norepinephrine, and serotonin.
"Consuming aspartame can lead to an excessive buildup of these neurotransmitters, resulting in serious side effects."
She added: "This accumulation can trigger hypertension, headaches, anxiety and insomnia, making it harder for individuals on MAOIs to manage their conditions."
For those taking these medications, it’s best to avoid or limit aspartame to prevent any risky interactions.
2. Caffeine
Doesn't mix well with: ADHD, anxiety and blood pressure medicines
Coffee is known for making people feel more alert, more productive - and even a bit jittery.
So it shouldn't come as a surprise that caffeine can affect how stimulant drugs - used to treat anxiety, high blood pressure and ADHD - work in the body.
Kiran said: "Caffeine, being a stimulant, can amplify the effects of medications like Adderall and Ritalin, potentially overstimulating the central nervous system.
"This can lead to heart palpitations, anxiety, tremors, and insomnia, making it harder to manage conditions like ADHD.
"Similarly, caffeine can counteract the calming effects of anti-anxiety medications, including SSRIs and SNRIs, potentially increasing anxiety and triggering panic attacks".
It can also interfere with the sedative effects of some anxiety medications, worsening sleep difficulties and raising cortisol levels, which can further exacerbate stress.
"And for those on blood pressure medications like beta-blockers or diuretics, caffeine can increase heart rate and blood pressure by stimulating adrenaline and norepinephrine, undermining the purpose of these drugs and increasing the risk of complications like stroke or heart attack," Kiran added.
Is aspartame bad for you? What we know about the sweetener’s health risks
Aspartame, a common artificial sweetener in the UK, is found in many diet drinks and low-sugar foods
The UK's Food Standards Agency (FSA) and European Food Safety Authority (EFSA) both classify it as safe within set consumption limits.
However, in 2023, the International Agency for Research on Cancer (IARC) labelled aspartame as "possibly carcinogenic to humans," based on limited evidence linking it to liver cancer.
Despite this, UK health authorities still regard it as low-risk in moderation.
Some research suggests potential links to headaches or mood swings, but findings remain inconclusive.
3. Glycyrrhizin
Don't mix well with: Blood pressure and antiarrhythmics medicines
Glycyrrhizin is a sugar found in black liquorice, a popular Halloween treat.
According to Kiran, this can interfere with blood pressure medications and antiarrhythmics, which are used to treat abnormal heart rhythms.
"The chemical causes sodium retention and potassium loss, leading to increased water retention and elevated blood pressure," she said.
"This directly counteracts the effects of blood pressure medications, which are designed to lower blood pressure."
Chomping on lots of liquorice while taking these medications can result in uncontrolled hypertension, a chronic condition where the pressure in your blood vessels is too high.
This, she said, "significantly increases the risk of cardiovascular issues like stroke or heart attack".
Kiran added: "Even small amounts of black liquorice eaten regularly can elevate blood pressure levels.
"The potassium loss caused by glycyrrhizin can also reduce the effectiveness of diuretics, which aim to expel excess water and sodium from the body.
"It can also interfere with antiarrhythmics by exacerbating heart rhythm issues, potentially leading to dangerous irregular heartbeats.
"Therefore, people on these medications should avoid consuming liquorice to prevent potentially serious health risks."
4. Food colouring
Don't mix well with: Allergy medicines
Halloween sweet treats tend to be very colourful.
But food colourings, used to give our treats their spooky orange and green shades, can interfere with the effectiveness of allergy meds - and even make allergies worse.
"Some people are sensitive to synthetic food dyes which may trigger allergic-like reactions including hives, itching, swelling and asthma-like symptoms," Kiran said.
"For individuals taking antihistamines to control allergies, consuming foods with these colourings can provoke new allergic responses, making it harder for the medication to manage symptoms like hives or hay fever.
"These dyes can also promote the release of histamine, the very substance antihistamines are designed to block, reducing the medication's efficacy.
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"Additionally, food colourings can interact with other additives, like sodium benzoate, further exacerbating symptoms in sensitive individuals."
This combination of factors can overwhelm the body’s ability to control allergic reactions, even when on antihistamines.