Hawthorn is generally a safe and very useful tree for humans due to its calmin and nutrition properties though people prescribed with internal medications must seek advice.

As with all natural remedies consumption of Willow
should be guided by a qualified herbalist or physician.
This information here is for information purposes only,
and certainly not for prescription.

best use ...  

early spring leaves good as an early vegetable, country folk call it 'bread and cheese', and any part of the tree, leaves and fruit famous as first aid for heart calming during palpitations, hence the English call it 'heartsease' - but for people consuming prescribed medications, care is needed.

qualities of Hawthorn are said to be ...

antispasmodic - relief of physical and muscular tension
cardiac - heart tonic sedative - calming relief of mental and nervous tension
febrifuge - lowers body temperature

Several researchers indicate Hawthorn tea or tincture can help to prevent stroke through being a tonic for the heart and moderates high cholesterol and beneficial for both high and high blood pressure. Hawthorn tree, leaves, blossom and fruit properties are also said to assist the strengthening of artery walls, reducing the risk of constricted arteries and reducing risk of blood clots.

Even so, care is needed with consumption is other medications are being consumed.

toxicity? ...  as all plants have a nourishing level and toxic level

If you are on heart, blood thinning, asthma or Viagra medication it is essential to consult a doctor before combining hawthorn with other medicines. Health care professionals are needed to guide and thoroughly investigate how consumption of hawthorn interacts with medications. The full benefit of hawthorn nutrition takes about six weeks while toxic reactions with medications could happen within hours.

Pregnant women are advised to avoid Hawthorn totally as it may increase the risk of miscarriage.

While consuming hawthorn it is essential to observe if you find you suffer insomnia, sweating and digestive upsets. If so, take a few days break from hawthorn if this happens. Then try the Hawthorn again in a more diluted form see if the symptoms return or not. Find the balance that is right for you.

As I have mentioned, it is a tradition with country folk to pick young hawthorn leaves and buds in spring when other vegetables and food used to be scarce. Hawthorn leaves are remarkable for taking hunger pangs away, just like a snack of 'bread and cheese' does for many people. Again, this is only wise for people not consuming prescribed medications.

to read about the crafting potential of Hawthorn, please click here