Tiger poison does not eat children, I believe that without the author's explanation, everyone understands the meaning of this idiom. This idiom is often used to describe that everyone has the heart to love his son. However, throughout the ancient history of our country, there are many emperors who have killed their own sons. Why could they bear to kill their own son?
By way of example, the author would like to tell why the ancient emperor was executed, so that everyone can understand why the emperor can make up his mind. The reason why the prince was executed was nothing more than these reasons.

First, the plot is wrong
In ancient times, the punishment was very severe, and it was necessary to impose capital punishment at every turn, and even to exterminate the Nine Tribes. Of these different crimes, treason is the most serious one. Even if you are a prince, as long as you have the heart to rebel, unless you can succeed in the end, you are doomed to have no good end.
For example, Shi Yi, the crown prince of The Later Zhao Wu Emperor Shi Hu, had always been deeply loved by his father, and Shi Hu often even said to the ministers: "Sima Shi's father and son brothers are killing each other, so they have been able to get here; if you kill Ah Tieli?" This means that Sima Shi's father and son brothers killed each other, which gave him what he is today, so he has no reason to kill Shi Yi. The implication is to praise their sons for loving each other.
But after a long time, Shi Hu punched himself in the face. Ishihime himself was arrogant and wanted not only to kill his brother, but also to kill his father and seize the throne. In the end, shi hu reduced his son to a commoner and sent someone to kill him that night.
After Shi Tao was executed, Shi Hu made his second son Shi Xuan crown prince, and Shi Xuan, jealous of his father's favor for his younger brother Shi Tao, wanted to assassinate his father at his brother's funeral. As a result, Shi Hu was known, and Shi Hu, who was extremely angry, sentenced his son to death, and Shi Xuan died under torture. His wife, children, and guards were executed.
2. Being framed
In fact, in history, the prince took the initiative to rebel, and very few were executed. For example, Tang Taizong's crown prince Li Chengqian plotted a rebellion, and although the matter was defeated, Tang Taizong did not execute Li Chengqian out of love for his son, but only abolished him as a commoner. Later, in order to save Li Chengqian's life, Tang Taizong had to abandon the more favored Li Tai as crown prince and establish the benevolent Li Zhi instead, on the grounds that: "Tai Li, Chengqian, and the King of Jin do not exist; the King of Jin, the King of Jin, and the King of Tai can be unharmed." ”
However, many of the princes who were framed by the emperor were executed by the emperor, and as for the charges of being framed, they were still "plotting against each other."
For example, Emperor Wu of Han's crown prince Liu Zhao, who was originally deeply loved by Emperor Wu of Han. However, as Empress Wei Zifu grew old and faded, Liu Zhu gradually fell out of favor. Affected by the scourge of witchcraft, Emperor Wu of Han mistakenly believed the rumors, believing that the prince was going to rebel, so he sent troops to suppress it. In the end, the crown prince Liu Zhi killed himself.
There were also three sons of Tang Xuanzong, Li Ying the Crown Prince, Li Yao the Prince of E, and Li Ju the Prince of Guang, who were framed by Concubine Wu Huifei, saying that the three of them were deliberately plotting rebellion, and only then were they deposed by Tang Xuanzong as Shuren, and they were all killed soon after.
Third, affect the interests of the emperor
Wu Zetian's eldest son Li Hong and second son Li Xian died successively, and there is controversy about the cause of Li Hong's death in later generations. Some think that he died of illness, and some think that he was killed by his mother Wu Zetian, so leaving aside Li Hong, Li Xian was indeed killed by Wu Zetian.
The reason why Wu Zetian killed his son was precisely because his interests were affected. After Li Hong's death, Li Xian was made crown prince, Li Xian was very good, had a lot of prestige in the dynasty, many ministers also supported him, and Emperor Gaozong of Tang also valued him. However, Wu Zetian thought that Li Xian was powerful and would not be easy to control in the future, so he tried to get rid of him.
Wu Zetian framed Li Xian for rebellion and forced Emperor Gaozong of Tang to depose him. Li Xian was exiled to Bazhou after several years of seclusion, and as soon as Emperor Gaozong of Tang died, Wu Zetian immediately sent someone to kill Li Xian. Although Wu Zetian was not yet an emperor at this time, her power was no different from that of an emperor.
Fourth, there are differences with the emperor
Tuoba Huang was the eldest son of Tuoba Tao, the Emperor Taiwu of the Northern Wei Dynasty, who believed in Buddhism and Emperor Taiwu believed in Taoism, which led to a disagreement between father and son.
In 446, Emperor Taiwu ordered the destruction of the Buddha, which was strongly opposed by Tuoba Huang. The two went against each other, and Emperor Taiwu gradually lost confidence in this son, and finally, in a fit of anger, Emperor Taiwu ordered the execution of Tuoba Huang's cronies, causing Tuoba Huang to fall ill. Although Tuoba Huang died of illness, the root cause of this disease was still caused by Emperor Taiwu.
In addition, there is another example of the Northern Wei.
In 494, Emperor Xiaowen of Northern Wei issued an edict stipulating that ethnic minorities in the north must wear Han costumes, and the wen and military officials also changed to the imperial clothes of Han officials. However, Emperor Xiaowen's crown prince Yuan Ke (元恂) disagreed with his father over Sinicization, and he insisted on opposing Sinicization. As a result, the relationship between father and son is getting worse and worse.
Yuan Ke's opposition to Sinicization was supported by many nobles who moved south, which undoubtedly put pressure on Emperor Xiaowen. In the end, Yuan Ke was demoted to a Shuren and imprisoned in Heyang. Soon Emperor Xiaowen sent people to execute Yuan Ke, who was only 15 years old at this time.
Having said these four reasons, I think everyone has already seen that the reason why the emperor killed his son fiercely is mainly because the imperial power is threatened. One might argue that imperial power is really more important than one's own son? Here the author has to say five words again, that is, "tiger poison does not eat children."
In fact, although this idiom is used to describe the heart of the beloved son, in real cases, the tiger will eat the cub. If the tiger finds that the cub smells wrong, or the cub is dead, the tiger will eat the cub.
Not only tigers, but even cat cubs die, and cats eat their children. In addition to felines, animals such as rabbits, sharks, and penguins will have this behavior.
So let's come back, is imperial power really more important than the son? The answer is of course. Once the son has a different heart, just like the little tiger has a peculiar smell, this is not his own child, and the emperor will naturally bear to kill it.
Speaking of "dragons give birth to dragons, phoenixes give birth to phoenixes", the emperor has so many sons, even if this is not useful, there is always one that satisfies him. Therefore, killing an indisputable son is not a great loss for the emperor, and this son is still a threat to himself. In ancient times, there were countless instances of cannibalism for the sake of imperial power, not to mention that fathers killed sons, and sons wanted to kill their fathers.
Of course, the situation that tiger poison does not eat children still exists. Just like the aforementioned Tang Taizong, it was out of the heart of his son that he did not execute li Chengqian, the rebellious crown prince.
There is also a Ming Taizu Zhu Yuanzhang, who knows that Zhu Yuanzhang likes to kill, and the founding heroes of the Ming Dynasty are about to be killed by him. However, Zhu Yuanzhang, who was so cruel, was very kind to his sons, and everything he did before he died was to pave the way for his children and grandchildren. It can be seen that not all emperors will kill their sons with all their hearts.
(References "Book of Jin", "Book of Wei", "New and Old Book of Tang", "Zizhi Tongjian", etc.)