THE POISON GARDEN website      Arum maculatum berries on a Cannabis leaf 


This free script provided by JavaScript Kit

Pontifications on Poison

Being some ramblings on events associated with poisonous plants.

Wednesday 28th November 2012

The original planting list for the Alnwick Garden Poison Garden contained some plants where the poisonous nature was rather obscure and some that had been included because of their use as antidotes. Because these plants led some people to be a bit sneery about the garden, there was a re-planting in 2006 with the intention of focussing on well-established poison plants.

There was also a problem with some plants that weren’t suited to the outdoor life in north-east England. One tree that fell into both those problem areas was Citrus aurantium, the orange. It had to be kept indoors for eight months of the year and its justification for being in the garden was the rather weak fact that some people get contact dermatitis from citrus oil.

Now, however, it seems that whilst the species may not have been a good choice the genus was. A paper in the Canadian Medical Association Journal (behind a paywall)1 was widely reported in both the mainstream and the scientific media. Since I haven’t even found a freely available abstract of the paper itself, I’ll rely on the New Scientist to report the story well.2

New Scientist reports that David Bailey of the University of Western Ontario in London, Canada, reviewed the literature and prescribing information of various drugs for any mention of a reaction with grapefruit, Citrus × paradise. Interaction between grapefruit and some prescribed medications has been known for some time but Bailey discovered that the number of such medications has risen 24% since 2008. He found 85 drugs mentioned as interacting with grapefruit and noted 43 of those as capable of causing severe adverse effects.

There is a chemical in the fruit that destroys an enzyme in the body that acts to break down other substances included drugs. Removing the enzyme means the medicine has a greater effect than expected. In the worst examples, one glass of juice could turn a normal dose of medication into an overdose. Though no cases seem to have occurred, it is said that grapefruit and certain cancer drugs could produce fatal consequences.

That thought brings me to homeopathy.

Some months ago, my wife received a questionnaire ahead of a hospital outpatient appointment. In part it asked for details of all medications she was taking whether prescribed or other the counter. It then said ‘Remember to include any inhalers, eye drops, creams, herbal or homeopathic remedies.’

I asked the hospital to explain why it included homeopathic substances when, being completely inert, they couldn’t possibly have a bearing on anyone’s medical condition. That was in August and, last week, I received a reply saying that the Senior Clinical and Development Pharmacist - Pharmacy Department had been consulted and explained that the reference is not intended to imply an endorsement of homeopathic remedies by NHS Borders.

I think I may have touched a nerve because later in the email the sender says ‘I must emphasise again that the use of this description is not in any way intended to suggest that NHS Borders endorses homeopathy as an alternative form of medical treatment’.

I’m assuming the form is intended to guide outpatient doctors when it comes to prescribing something for the condition in front of them. Drug interactions can be very dangerous so it is essential for a doctor to consider what interactions may arise from the medication they are providing to a patient who has not taken it before. I don’t suppose that a doctor has ever decided against providing a proper medicine because the patient is taking sugar pills.

What is not on the form but, it appears, should be, is to ask about the patient’s diet; and not just whether they have grapefruit. I remember being told by a pharmacist that she had been involved in a clinical trial of a new drug and one of the subjects had a response completely unlike any of the others. Only when looking into it did they discover that he drank enormous amounts of coffee and the caffeine had interacted with the trial medication.

Still it is good to know that NHS Borders does not endorse homeopathy. I hope they have said as much to their neighbour, NHS Lothian, currently undertaking an online survey to see if it should fund homeopathy.


1. Grapefruit-medication interactions: Forbidden fruit or avoidable consequences? First published November 26, 2012, doi: 10.1503/cmaj.120951 CMAJ November 26, 2012 cmaj.120951
2. Grapefruit makes drugs pack a stronger punch New Scientist Issue 2893 27 November 2012.

Submit a Comment

You can send comments via the contact page but please be sure to say what blog entry you are commenting on.

Follow @thepoisongarden on Twitter

Full Entries


Tuesday 25th October 2016 Saturday 20th August 2016 Sunday 6th March 2016 Wednesday 3rd February 2016


Saturday 28th November 2015 Friday 27th November 2015 Monday 17th August 2015 Wednesday 15th July 2015 Friday 26th June 2015 Thursday 25th June 2015 Thursday 30th April 2015 Wednesday 29th April 2015 Wednesday 11th March 2015 Tuesday 3rd March 2015 Saturday 28th February 2015 Sunday 22nd February 2015

November 2014


Monday 24th November 2014 Saturday 8th November 2014

October 2014

September 2014

Wednesday 24th September 2014 Monday 1st September 2014

August 2014

Tuesday 26th August 2014 Saturday 16th August 2014 Tuesday 5th August 2014 Friday 1st August 2014

July 2014

Sunday 27th July 2014 Wednesday 23rd July 2014 Sunday 13th July 2014 Sunday 6th July 2014 Tuesday 1st July 2014

June 2014

Wednesday 25th June 2014 Tuesday 24th June 2014 Sunday 22nd June 2014 Monday 9th June 2014 Wednesday 4th June 2014

May 2014

Monday 26th May 2014 Sunday 18th May 2014 Wednesday 14th May 2014

April 2014

Sunday 13th April 2014 Saturday 5th April 2014 Thursday 3rd April 2014 Tuesday 1st April 2014

March 2014

Monday 31st March 2014 Tuesday 25th March 2014 Friday 21st March 2014 Monday 17th March 2014 Sunday 16th March 2014 Tuesday 11th March 2014 Thursday 6th March 2014 Wednesday 5th March 2014 Saturday 1st March 2014

February 2014

Thursday 27th February 2014 Monday 24th February 2014 Wednesday 19th February 2014 Monday 17th February 2014 Thursday 13th February 2014 Monday 4th February 2014 Monday 3rd February 2014 Saturday 1st February 2014

January 2014

Thursday 28th January 2014 Thursday 23rd January 2014 Friday 17th January 2014 Wednesday 15th January 2014 Monday 13th January 2014 Thursday 9th January 2014 Tuesday 7th January 2014 Wednesday 1st January 2014

December 2013

Monday 23rd December 2013 Friday 20th December 2013 Tuesday 17th December 2013 Friday 14th December 2013 Thursday 12th December 2013 Sunday 8th December 2013 Wednesday 4th December 2013 Sunday 1st December 2013

November 2013

Friday 29th November 2013 Wednesday 27th November 2013 Tuesday 26th November 2013 Friday 22nd November 2013 Monday 18th November 2013 Friday 15th November 2013 Thursday 14th November 2013 Sunday 10th November 2013 Thursday 7th November 2013 Wednesday 6th November 2013 Friday 1st November 2013

October 2013

Thursday 31st October 2013 Sunday 27th October 2013 Wednesday 23rd October 2013 Monday 21st October 2013 Friday 18th October 2013 Friday 11th October 2013 Wednesday 9th October 2013 Tuesday 8th October 2013 Monday 7th October 2013 Tuesday 1st October 2013

September 2013

Monday 30th September 2013 Saturday 28th September 2013 Friday 27th September 2013 Monday 23rd September 2013 Sunday 15th September 2013 Monday 9th September 2013 Sunday 8th September 2013 Tuesday 3rd September 2013 Sunday 1st September 2013

August 2013

Tuesday 27th August 2013 Sunday 25th August 2013 Monday 19th August 2013 Friday 16th August 2013 Tuesday 13th August 2013 Friday 9th August 2013 Friday 2nd August 2013 Thursday 1st August 2013

July 2013

Saturday 27th July 2013 Sunday 21st July 2013 Wednesday 17th July 2013 Monday 15th July 2013 Saturday 13th July 2013 Friday 12th July 2013 Thursday 11th July 2013 Wednesday 10th July 2013 Tuesday 9th July 2013 Saturday 6th July 2013

June 2013

Friday 28th June 2013 Tuesday 25th June 2013 Friday 21st June 2013 Thursday 20th June 2013 Wednesday 19th June 2013 Saturday 15th June 2013 Sunday 9th June 2013 Saturday 8th June 2013 Saturday 1st June 2013

May 2013April 2013 March 2013 February 2013 January 2013 December 2012 November 2012 October 2012 September 2012 August 2012 July 2012 blog June 2012 blog May 2012 blog April 2012 blog March 2012 blog February 2012 blog January 2012 blog December 2011 blog November 2011 blog October 2011 blog September 2011 blog August 2011 blog July 2011 blog June 2011 blog


The POISON GARDEN website is not connected with Alnwick Garden Enterprises Ltd and/or The Alnwick Garden Trust.