Drunken Angel (醉いどれ天使, Yoidore Tenshi) is a 1948 Japanese yakuza film directed by Akira Kurosawa, and co-written by Kurosawa and Keinosuke Uekusa. Produced by Toho and starring Takashi Shimura and Toshiro Mifune, it tells the story of alcoholic doctor Sanada, and his recidivist yakuza patient Matsunaga. Sanada tries to save Matsunaga from illness and the corruption of the yakuza while Matsunaga finds himself gradually sidelined within the yakuza syndicate and becomes increasingly self-destructive. The film was the first to depict the post–War yakuza and is generally considered to be Kurosawa's first major work.

During the writing of the screenplay Kurosawa and Uekusa fought about Uekusa's growing sympathies with the yakuza due to his regular meetings with a life-model to study for the character. Production began in 1947 amid a series of labour disputes in the Toho company. Filming lasted from November of that year to March 10, 1948. During the production of the film Kurosawa encountered a number of setbacks, including the death of his father in February 1948. The film was the first of sixteen collaborations between Kurosawa and Mifune, and the first collaboration between Kurosawa and Fumio Hayasaka. It was in the production of Drunken Angel that Kurosawa began to think more about music's relationship to the image in film.

Despite encountering some censorship from the Civil Information and Education Section of the Allied occupation government, the film was released in Japan on April 27, 1948, to generally positive reviews. The film won awards for Best Film from Kinema Junpo and Mainichi Shimbun. After the international success of Rashomon (1950) at the 1951 Venice Film Festival, Toho promoted the film abroad. Analyses of Drunken Angel have looked at the pairing of multiple characters and their interactions in the post–War environment, with discussions focussing on the morality of its characters (the titular "drunken angel"), intertextual references to the novels of Fyodor Dostoevsky and contemporary noir fiction, and the symbolic meaning of the sump seen throughout much of the film.

Sanada is an alcoholic doctor living in a shanty town next to an open sump. He treats a small-time yakuza named Matsunaga—who was injured in a gunfight with a rival syndicate—despite his dislike of organised crime. Sanada diagnoses Matsunaga with tuberculosis; Matsunaga initially reacts violently but the two of them are interrupted by the arrival of Sanada's nurse Miyo. The following day Sanada goes to a bar in the local black market, which Matsunaga controls, and attempts to persuade Matsunaga to give up drinking and smoking. After Matsunaga kicks Sanada out of the bar, Sanada and Miyo discuss the imminent release from prison of Matsunaga's fellow yakuza and sworn brother, Okada, Miyo's abusive ex-boyfriend. Sanada continues treating his other patients, one of whom, a young female student, is making progress against her tuberculosis. After some pestering, Matsunaga agrees to listen to the doctor's advice and quit drinking.

However, with Okada's release, Matsunaga quickly succumbs to peer pressure and slips back into vice together with his fellow yakuza. Angered at the betrayal of his commitment, Sanada rebukes him. Matsunaga finds himself gradually displaced within the yakuza syndicate, and after losing a large amount of money playing chō-han, he collapses and is taken to Sanada's clinic for the evening. Distressed as his lover leaves him and his illness takes a turn for the worse, Matsunaga leaves his apartment and is confronted by Sanada at the open sump. Sanada beseeches Matsunaga to continue his treatment, while Matsunaga has a vision of his own corpse trying to kill him. Okada shows up at the clinic and threatens to kill the doctor if he does not tell him where to find Miyo, and while Matsunaga stands up for the doctor and gets Okada to leave, he realises that his sworn brother cannot be trusted.

Hoping to resolve the issue, Matsunaga goes to the home of the boss of his syndicate but overhears a discussion in which Okada says he intends to sacrifice him as a pawn in the war against a rival syndicate. Distressed and self-destructive, Matsunaga orders a drink from Gin, a local barmaid, who tries to persuade him to seek treatment in the countryside. The boss returns the territory of the black market to Okada, who orders the storeowners in his territory to refuse service to Matsunaga. He goes to Okada's apartment; there, he finds the yakuza with his former lover, and angrily tries to stab Okada, but starts to cough up blood. Okada then stabs him in the chest, and Matsunaga stumbles outside before he succumbs to his wounds and dies.

Okada is later arrested for the murder, but Matsunaga's boss refuses to pay for his funeral. Gin, who had feelings for Matsunaga, pays for it instead and tells Sanada that she plans to take Matsunaga's ashes to be buried on her father's farm, where she had offered to live with him. The doctor retorts that while he understands how she feels, he cannot forgive Matsunaga for throwing his life away. Another of his patients, the female student, arrives and reveals that her tuberculosis is cured. The doctor happily leads her to the market to buy her sweets.

Drunken Angel was made in the context of a series of labour disputes with the Toho company. The powerful trade union had managed the production of films, with Kurosawa's prior films No Regrets for Our Youth (1946) and One Wonderful Sunday (1947) requiring the approval of the union. By the end of 1947, the union influence that had been exerted over the content of films produced by Toho began to wane following a series of less profitable releases. As a result, Kurosawa was able to produce the film with minimal interference from the studio and its union. Kurosawa co-wrote the film with his childhood friend Keinosuke Uekusa in their second and last collaboration. While staying at an inn at the seaside resort Atami, Kurosawa noticed that the prow of a sunken concrete ship was being used as a diving board by local children. Seeing it as an apt metaphor for Japan's defeat in the Second World War, this image became the open sump seen in Drunken Angel. Kurosawa intended to write the film to report on—and denounce—the growing power of the yakuza in post–War Japan.