Is Crown of Thorns Poisonous or Carcinogenic? A Detailed Guide to Household Care Precautions

Crown of Thorns (Euphorbia milii), also commonly known as iron begonia, has both the resilience of plum blossom and the charm of begonia. Its flowering period is very long, and with proper care it can basically stay in bloom all year round, making it a relatively popular flower in recent years. However, there is also quite a bit of controversy surrounding Crown of Thorns, such as whether keeping Crown of Thorns at home is poisonous or carcinogenic. What are the usual care precautions?

I. Is Crown of Thorns poisonous?

1. The sap of Crown of Thorns is poisonous

If you cut a slit in the body of a Crown of Thorns plant, or accidentally injure it, you will find a milky white sap flowing out from the plant. These milky white liquids belong to diterpenoid compounds and are strongly toxic. They are a defense mechanism that Crown of Thorns established during evolution to protect itself from pests and diseases.

The toxicity of this sap to the human body is mainly shown in:

(1) Contact with the skin can cause itching, redness and swelling;

(2) Ingestion can cause vomiting, abdominal pain, dizziness and headache, and symptoms may differ among different groups of people.

(3) Accidental entry into the eyes may cause eye diseases of varying severity, and the risk of blindness cannot be ruled out.

2. The thorns of Crown of Thorns are not poisonous

Beneath the beautiful and distinctive flowers of Crown of Thorns are layer upon layer of sharp thorns. Many people worry about whether these are poisonous, but in fact the thorns of Crown of Thorns are not toxic. It is just that after being pricked, some people may develop symptoms such as redness and swelling; simply wash promptly with clean water.

II. Is Crown of Thorns carcinogenic?

Although the sap of Crown of Thorns is poisonous, it has not reached the level of being carcinogenic. Although in earlier years the claim that “Crown of Thorns causes cancer” made many people panic, leading to many Crown of Thorns being “cleared out”, later many professional plant researchers and medical workers came forward to refute the rumor. Some substances in the sap of Crown of Thorns do indeed have a cancer-promoting effect when they accumulate to a certain amount, but they do not have an absolute carcinogenic effect.

As long as you do not come into long-term contact with or consume such substances, there is no need to worry too much about this.

III. What precautions should be taken when keeping Crown of Thorns at home?

1. Pay attention to the placement location

The placement location should avoid being within the reach of children in the household, and it is best not to place it in a corridor. A balcony specifically used for growing flowers is preferable, and a certain level of ventilation should be ensured.

2. Be careful not to touch the morning dew on the plant

Plants also have metabolic functions, so it is best not to touch, and even more so not to consume, the morning dew that accumulates on the plant itself in the morning.

3. Do not pick the flowers, stems or leaves without protective measures

When picking the flowers, stems or leaves of Crown of Thorns, the sap will flow out, thereby releasing toxic substances that can easily enter the mouth and nose and harm health. Therefore, if you need to carry out this kind of pruning operation, it is best to wear permeable-resistant gloves and wash the gloves and hands with soapy water after pruning.