*683OPINION ON APPELLANT’S PETITION FOR DISCRETIONARY REVIEW
MANSFIELD, Judge.A jury found appellant, Daniel Charles Sutton, guilty of driving a motor vehicle in a public place while intoxicated with alcohol.1 The trial court assessed appellant’s punishment at confinement in the county jail for two years, probated, and a fine of $500. The Seventh Court of Appeals affirmed the judgment of the trial court. Sutton v. State, 858 S.W.2d 648 (Tex.App.—Amarillo 1993). We granted appellant’s petition for discretionary review, pursuant to Texas Rule of Appellate Procedure 200(c)(2), to determine whether the jury charge authorized conviction on a theory not alleged in the information. We will affirm the judgment of the court of appeals.
Appellant was charged by information with driving while intoxicated with alcohol. In relevant part, the information alleged that appellant,
on or about the 27th day of May, A.D.1989, in the County of Dallas and State of Texas, did then and there drive and operate a motor vehicle in a public place ..., to wit: a street and highway, while intoxicated, in that [appellant] did not have the normal use of his mental and physical faculties by reason of the introduction of alcohol into [his] body.
Several witnesses testified at appellant’s trial. Rosie Nash testified that at approximately 10:00 p.m., May 27, 1989, after she stopped her car at a red light in Dallas County, another car hit her ear from behind. After the collision, Nash exited her car and walked over to the car that had hit her. Although the driver of the other car said nothing, Nash believed him to be intoxicated with alcohol because he staggered and because she “could smell it on him.”
Dallas Police Officer Archie King testified that he arrived at the scene of the collision at approximately 11:00 p.m. and found appellant still behind the wheel of his car. King arrested appellant after concluding that he was intoxicated with alcohol. King’s conclusion was based on appellant’s inability to stand unassisted, his slurred speech, and “a strong smell of alcohol coming from his breath.”
Dallas Police Officer Greg Williams testified that after appellant was brought to a Dallas police station at approximately 11:10 p.m., he (i.e., appellant) refused to give a breath or blood sample. Williams also testified that appellant, while at the police station, “had a strong smell of alcohol coming from his mouth,” that he “had a strong sway,” and that he was unable to “comply with ... instructions that were relatively simple.” Based on his experience and observations, Williams concluded that appellant was intoxicated with alcohol.
Appellant then took the stand in his defense and testified that he had no memory of the collision with Nash’s car, although he did recall being behind the wheel of his car shortly after the collision. He testified further that, in the hours preceding the collision, he ingested two pills of the drag Klono-pin, prescribed for him by his doctor; that his doctor never warned him to avoid mixing alcohol and Klonopin; that about thirty minutes before the collision, he consumed two beers; and that he found himself in “a precarious situation” on the night in question *684“not because of alcohol [but] because of [his] medication.”
Finally, defense witness John T. Castle, the owner-director of a forensic science laboratory in Dallas, testified that Klonopin, even taken properly, causes drowsiness in approximately fifty percent of users and “the appearance of intoxication” in approximately thirty percent of users; that an adult male taking Klonopin a few hours before drinking two beers “very likely ... would appear to be intoxicated on alcohol”; and that even one beer “would enhance the effect of the Klono-pin.” He also conceded that a Klonopin user could drink enough alcohol to become intoxicated from alcohol alone.
In its charge to the jury, the trial court instructed the jurors first that they could find appellant guilty if they found beyond a reasonable doubt that he had driven or operated a motor vehicle in a public place while intoxicated, “in that [he] did not have the normal use of his mental or physical faculties by reason of the introduction of alcohol into [his] body, as charged in the Information.” The trial court also instructed the jury, over appellant’s objection, as follows:
You are further instructed that if a Defendant indulges in the use of Klonopin to such an extent that he thereby makes himself more susceptible to the influence of alcohol than he otherwise would have been, and by reason thereof becomes intoxicated from recent use of alcohol, he would be in the same position as though his intoxication was produced by the use of alcohol alone.
Now, therefore, if you find and believe from the evidence beyond a reasonable doubt that the Defendant, Daniel Charles Sutton, on or about the 27th day of May, A.D.1989, in the County of Dallas and State of Texas was intoxicated, in that the Defendant did not have the normal use of his mental or physical faculties by reason of the introduction of alcohol into his body, and while so intoxicated, by reason of the introduction of alcohol into his body, either alone or in combination with Klonopin, and on the said date did then and there drive or operate a motor vehicle in a public place, to wit: a street and highway ..., you will find the defendant guilty as charged in the information....
(Emphasis added.) The jury subsequently found appellant guilty “as charged in the Information.”
On appeal, appellant argued that the jury charge, by authorizing conviction “by reason of the introduction of alcohol into [his] body, either alone or in combination with Klono-pin,” authorized conviction on a theory not alleged in the information. Appellant argued further that, under Garcia v. State, 747 S.W.2d 379 (Tex.Crim.App.1988), a jury charge may not authorize conviction for driving while intoxicated with a combination of intoxicants unless the State has first alleged that combination in the charging instrument. The court of appeals, relying upon our decision in Heard v. State, 665 S.W.2d 488 (Tex. Crim.App.1984), held that the trial court’s jury charge “did not authorize appellant’s conviction on a theory not alleged in the information; instead, the [trial] court merely applied the law to the facts of this prosecution.” Sutton v. State, 858 S.W.2d at 651.
The issue presented to this Court in Heard was identical to the issue presented to us in this case. In Heard, the defendant was charged by information with driving a motor vehicle in a public place while “under the influence of intoxicating liquor.”2 After the State rested its case, defense witness Dr. Norman Kaplan testified that the defendant was his patient at the time of the offense and that she was, at his instruction, taking various medications for treatment of hypertension. Kaplan testified further that a person in the defendant’s condition acting under the influence of those medications might appear intoxicated with alcohol, and that the mixing of those medications with alcohol might cause *685a person to lose his mental acuity more quickly than if he was only drinking alcohol. The defendant herself then testified that she had drunk no alcohol on the day of the offense but that she had taken all of her medications. The trial court later instructed the jury in a manner essentially identical to the manner in which the trial court instructed the jury in this case, and the defendant was found guilty. The Eleventh Court of Appeals reversed, holding that the charge allowed the jury to convict on a theory not alleged in the information. We then reversed the judgment of the court of appeals, explaining:
The jury was appropriately charged that they could convict appellant upon finding that her intoxication was due to liquor alone or a combination of liquor and drugs. Under our case law, this combination of liquor and drugs which would make an individual more susceptible to the influence of the liquor is in effect equivalent to intoxication by liquor alone. Thus, the trial court’s charge did not expand on the allegations of the information but merely applied the facts of this particular case to the law. There is no error.
Heard v. State, 665 S.W.2d at 490 (emphasis added; citation omitted).
Our holding in Heard is dispositive of this case.3 The trial court’s charge at appellant’s trial, like the charge at Heard’s trial, did not expand on the allegations in the information. Rather, the charge at appellant’s trial, when read carefully, allowed conviction only if the jury found that appellant had been intoxicated with alcohol, either alone or in combination with a drug that made him more susceptible to the alcohol. In either ease, the jury had to find that appellant had been intoxicated with alcohol, not with the drug. The jury clearly did so, finding appellant guilty “as charged in the information,” which means the jury found him intoxicated due solely by reason of the introduction of alcohol into his body. The jury did not find appellant guilty due to intoxication by reason of ingestion of Klono-pin or ingestion of Klonopin and alcohol. Even accepting appellant’s argument that the jury charge impermissibly expanded on the allegation in the information, he fails to show any resulting harm.
It was appellant himself who presented evidence that his use of a prescription drug contributed to his condition at the time of the collision. Once appellant introduced this evidence, the trial court was obligated to instruct the jury on the law as explicated in Heard. See Tex.Code Crim.Proc. art. 36.14.
Appellant’s reliance upon Garcia is misplaced, because the issue in that case was quite different. In Garcia, we held that in the face of a timely motion to quash, a charging instrument in any DWI prosecution must specify the type(s) of intoxicant allegedly used by the defendant. Here, appellant made no such motion to quash.
Having discerned no error, we AFFIRM the judgment of the court of appeals.
MEYERS, J., concurs in the result. OVERSTREET, J., dissents.. At the time of appellant’s offense, Texas Revised Civil Statutes article 6701Z-1 provided in relevant part:
(a) In this article:
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(2) "Intoxicated” means:
(A) not having the normal use of mental or physical faculties by reason of the introduction of alcohol, a controlled substance, a drug, or a combination of two or more of those substances into the body; ...
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(b) A person commits an offense if the person is intoxicated while driving or operating a motor vehicle in a public place. The fact that any person charged with a violation of this section is or has been entitled to use a controlled substance or drug under the laws of this state is not a defense.
(Emphasis added.) See now Tex.Penal Code § 49.04.
. At the time of Heard's offense, October 2, 1980, Tex.Rev.Civ.Stat.Art. 6701(7 )-l provided: "Any person who drives or operates an automobile or any other motor vehicle upon any public road or highway in this State ... while such person is intoxicated or under the influence of intoxicating liquor, shall be guilty of a misdemeanor....” The statute at that time did not define the terms intoxicated or under the influence of intoxicating liquor, nor was there any language referring to an intoxication by reason of ingestion of a drug or a combination of alcohol and a drug.
. It is noted that the statute in effect at the time of Heard’s offense (see footnote 2) did not define the term "intoxicated" and did not contain any language to cover situations in which intoxication may be the result of ingestion of a combination of one or more drugs and alcohol, or the result of ingestion of one or more drags and no alcohol. The fact that the statute has been amended (see Tex.Pen.Code 49.01 through 49.10) does not, in our opinion, invalidate the reasoning in Heard.