OPINION OF THE COURT
WEINER, District Judge.The appellant in this diversity case seeks to overturn a jury verdict rendered in favor of the defendant, the Metropolitan Life Insurance Company. The jury found that the appellant was not entitled to recover accidental death insurance benefits under two policies covering her deceased husband. The trial judge entered judgment for the defendant, and denied the appellant’s motion for a new trial. Upon review of the evidentiary rulings and jury instructions which have been attacked by the appellant, we conclude that no error was committed by the court below. Accordingly we affirm the judgment and the denial of appellant’s motion for a new trial.
The record shows that on October 7, 1974, the appellant’s husband, Walter Pollard, a resident of Greensburg, Pennsylvania, was in Hampton, South Carolina for a business conference. He and his co-workers were assigned separate bedrooms at the Micarta Lodge, which was owned by their employer, the Westinghouse Electric Corporation. That evening, Mr. Pollard and several other employees dined at a restaurant that served alcoholic beverages. After dinner, Pollard and his co-workers returned to the Lodge where, after a short time, Pollard’s speech became slurred and he stumbled when attempting to rise from his seat. Believing that Pollard was drunk, two co-workers escorted Pollard to his room and placed him on his bed fully clothed. The next morning, Pollard was found dead in his room.
A necropsy report indicated that Pollard died as a result of asphyxia due to aspiration of his gastric contents caused by acute alcohol and drug intoxication.1 The report also showed enlargement and fatty degeneration of his liver, and mild to moderate atherosclerosis.
The decedent was insured by the defendant, the Metropolitan Life Insurance Co., under two group insurance policies providing for benefits upon accidental death. Under the terms of the policies, in order to recover, death must have occurred to the insured, “solely by violent, external and accidental means”. Both policies contain a clause which bars payment of death benefits when death is caused by or results from “intentional self-destruction or intentionally self-inflicted injury while sane or insane”. Citing the ingestion of alcohol and tranquilizers by the decedent, and the enlargement and fatty degeneration of the decedent’s liver, the defendant refused to pay Pollard’s widow the death benefits provided by the policies.
At trial, the appellant sought to introduce into evidence the death certificate, coroner’s certificate (cause of death memorandum) and pathologist’s (necropsy) report. Her first ground for reversal is that the trial judge erred when he ruled that the documents would be admitted into evidence only if statements contained within them, which declared that the death was accidental, *1286were excised.2 It was ostensibly because of this limitation that the appellant ultimately decided not to present the documents to the jury. (Tr. 430).
We must first determine which body of law is looked to when deciding whether the limitation imposed on the admissibility of the documents was erroneous. The appellant asserts that since Pennsylvania law governs the rights of the parties under the insurance contract, Pennsylvania evidentiary law is controlling with regard to the admissibility of the death certificate. She also contends that along with the Federal Rules of Evidence, Pennsylvania law is looked to with regard to the admissibility of the coroner’s certificate and pathologist’s report. The appellee maintains that the Federal Rules of Evidence control these evidentiary issues.
We hold that the Federal Rules of Evidence govern the admissibility of documentary evidence in Federal diversity cases.3 Kingsley v. Baker/Beech-Nut Corp., 546 F.2d 1136, 1140 (5th Cir. 1977); Conway v. Chemical Leaman Tank Lines, Inc., 525 F.2d 927, 930 (5th Cir. 1976). See United Telecommunications v. American Tel. & Communications Corp., 536 F.2d 1310, 1316 (10th Cir. 1976). The rules were enacted by Congress to “govern proceedings in the courts of the United States”. Rule 101. While the rules do show a desire by Congress to defer to state law in diversity cases on such matters as presumptions (Rule 302), privileges (Rule 501) and competency (Rule 601), there is no similar deference concerning the admissibility of documentary evidence.
The law is well settled that we are to review a trial judge’s discretionary determination using the “manifestly erroneous” standard. Atlantic Mutual Insurance Co. v. Lavino Shipping Co., 441 F.2d 473 (3d Cir. 1971); United States v. Lopez, 543 F.2d 1156, 1158 (5th Cir. 1976) cert. denied, 429 U.S. 1111, 97 S.Ct. 1150, 51 L.Ed.2d 566 (1977). An examination of the record indicates that the limitation imposed on the admission of the documents did not violate the Federal Rules of Evidence. Under Rule 403, a trial judge can exclude relevant evidence “if its probative value is substantially outweighed by the danger of unfair prejudice . .
The following factors support our conclusion that the trial judge’s ruling was not “manifestly erroneous”. The death certificate and coroner’s certificate report describe the cause of death as asphyxia due to aspiration of gastric contents due to acute ethanol intoxication, and conclude that death was accidental. However, the probative value of these documents undoubtedly was slight, because they were prepared pri- or to October 16, 1974, when the toxicologist’s report was completed.4 Moreover, Dr. Brissie, the consulting pathologist who assisted in the preparation of the necropsy report, testified that he did not serve as a medical examiner for the coroner. He also testified that in view of the information added by the toxicologist’s report, he certainly would amend the cause of death form. (Tr. 207-209)
To be balanced against the probative value is the evidence’s prejudicial effect. Dr. Brissie testified that he was neither requested to investigate this death, nor informed of the precise language of the acci*1287dental death provision of the policy. (Tr. 209-210). It is apparent that if the documents had been freely admitted into evidence, without limitation on content, the jury would have been misled into believing that the documents were based on a comprehensive investigation grounded on complete information and that Dr. Brissie’s conclusion as to the manner of death took into consideration the language used in the policy-
In addition, it must be noted that the coroner is required to make a determination regarding the cause of death. Though he is to determine whether the death was a homicide, a suicide or an accident, and is to conclude whether it was natural or undetermined, his decision is not binding for purposes of suit, for it is used merely for statistical purposes and to guide the district attorney’s office and/or any parties. (Tr. 207-209)
Another factor which the court undoubtedly believed would prejudice the jury was the fact that the term “accidental death”, as defined in the policy, may well have had a different meaning than that term as used by Dr. Brissie in his report.
Lastly we note that the trial judge’s ruling did not keep objective factors from the jury. He states:
“The exhibits that refer to [the] accident need not be given to the jury. If they make a request, we will give it to them in an appropriate form.” (Tr. 429-430)
Appellee’s counsel then suggested that the word accident could be blanked off. We find the judge’s ruling to be a precautionary measure taken to safeguard the jury from prejudice. After defining the word “accidental” in both its everyday usage and as used in the policy, he properly left to the jury the determination whether the evidence and objective factors proved “accidental death”. We therefore conclude that his rulings on this point were not “manifestly erroneous”.5
The appellant further argues that several portions of the court’s charge to the jury were not in accordance with Pennsylvania law, which both parties agree controls the substantive issues at bar. Erie R. Co. v. Tompkins, 304 U.S. 64, 58 S.Ct. 817, 82 L.Ed. 1188 (1938); Daburlos v. Commercial Ins. Co. of Newark, N. J., 521 F.2d 18, 19 (3rd Cir. 1975). One alleged error involves the “presumption against suicide”. The court instructed the jury that in determining whether Mr. Pollard’s death was accidental or intentional, the jury is, “permitted to consider the fact that there is in human nature, an instinct for self-preservation. But these circumstances does (sic) not in and of itself establish the fact that Mr. Pollard died through accidental means”.
The .appellant appears to assert that the jury should have been instructed that in the absence of facts establishing otherwise, it should presume accidental death. Ironically, this contention ignores the very case on which the appellant primarily relies. In Watkins v. Prudential Ins. Co., 315 Pa. 497, 173 A. 644 (1934) the Pennsylvania Supreme Court stated that the “so-called presumption against suicide,” is “merely a permissible consideration of the non-probability of death by suicide,” and properly speaking is not a presumption at all. It is a well established rule that on the issue of accidental death, it is the plaintiff who has the ultimate burden of establishing that death resulted from an accident rather than from suicide. Id., 315 Pa. 497, 505, 506, 173 A. 644, 648-649; Waldron v. Metropolitan Life Ins. Co., 347 Pa. 257, 31 A.2d 902 (1943); Heffron v. Prudential Ins. Co. of America, 144 Pa.Super. 307, 19 A.2d 556 (1941). The judge’s instruction regarding the presumption against suicide is therefore a correct statement of Pennsylva*1288nia law. Although the appellant cites MacDonald v. Penn. R.R., 348 Pa. 558, 36 A.2d 492 (1944), neither it nor other Pennsylvania decisions lead to a contrary view.
The appellant advances several other contentions, each of which is easily disposed of. She asserts that the court below did not properly charge the jury on the weight to be accorded to the expert testimony presented at trial, because it failed to state that opinion evidence is the “weakest form of evidence”. The court instructed the jury that it “should consider each expert opinion received in evidence in this case and give it such weight as you think it deserves. You may accept the opinion or reject it entirely”. While an instruction such as that advocated by the appellant might be called for when the opinion of an expert was in clear contradiction to “positive evidence of actual facts”, Kuchinic v. McCrory, 439 Pa. 314, 319, 266 A.2d 723, 725-726 (1970); Ray v. Philadelphia, 344 Pa. 439, 441-42, 25 A.2d 145, 146 (1942), the testimony of the medical experts in this case regarding the cause of death was consistent with factual evidence presented at the trial. Accordingly, the judge’s instruction was correct. See Marrazzo v. Scranton Nehi Bottling Co., 422 Pa. 518, 223 A.2d 17 (1966); Masciantonio Will, 392 Pa. 362, 383—384, 141 A.2d 362, 372-373 (1958).
As another ground for reversal, the appellant contends that the trial judge incorrectly charged the jury on the meaning of “accidental” death. The judge stated that the term “accidental” means “undesigned, unexpected and unpremeditated”. He told the jury that if it found that “the substances that caused asphyxiation were intentionally taken by Mr. Pollard for the purpose of self-destruction or for the purpose of inflicting serious bodily injury on himself”, (emphasis supplied) then it should not find that the insured’s death was accidental.6
The appellant cites Beckham v. Travelers Ins. Co., 424 Pa. 107, 225 A.2d 532 (1967) in support of her assertion that the above instruction is in conflict with the governing Pennsylvania law on the subject of accidental death. In Beckham, the Pennsylvania Supreme Court abolished the rule that denied recovery of insurance benefits for accidental death, “if the insured’s death, although unintentional, resulted from an intentional act of the deceased”. Id., at 110, 225 A.2d at 533. In abandoning its former rule, the court allowed recovery under an insurance policy covering death “through accidental means”, in a case where the occurrence of death was accidental, and the acts leading to death, although intentionally committed, were not engaged in by the insured for the purpose of committing suicide. However, the court countenanced the inclusion of contractual limitations in insurance policies which would disclaim coverage when the insured intentionally exposed himself to danger. Id. at 117, 225 A.2d at 537.
In light of the above, the court’s instruction must be regarded as proper. The court did not state that the jury should find that death was not accidental if it merely found that the decedent intentionally, although without suicidal intent, ingested the substances causing asphyxiation. Instead, the court charged that in determining whether the plaintiff had met her burden of showing that death was accidental, the jury should decide whether the substances were intentionally ingested “for the purpose of self-destruction”. Moreover, in instructing the jury that it could make a finding that death was not accidental if it determined that the substances were intentionally taken by the deceased for the purpose of “inflicting serious bodily injury on himself”, the court was merely restating a clause in the insurance policies which barred recovery for such deaths.
*1289Having found that the appellant’s arguments are without merit,7 the judgment of the district court is affirmed.
. A toxicological examination revealed that Pollard had a blood ethanol level of 322 mgm./dl. A urine drug screen revealed Pentobarbital, Phenothiazine and Propoxyphene. The blood levels were: Pentobarbital 2.1 mgm./100 cc., Propoxyphene 0.4 mgm./100 cc., Phenothiazine 1.6 mgm./100 cc.
. Although the appellant states in her brief that the court “refused to permit the foregoing materials to be submitted to the jury”, the transcript shows that the judge would have admitted the materials subject to the limitation. (Tr. 429)
. The Federal Rules of Evidence apply to actions brought “subsequent to the one hundred and eightieth day after January 2, 1975” (July 1, 1975). Pub.L. 93-595. Although this case was instituted on June 30, 1975, the statute adopting the Rules also states that they are to apply to “further procedure in actions, cases and proceedings then pending except to the extent that application of the rules would not be feasible or would work injustice”. Since this case was tried on June 13, 14, and 15, 1977, almost two years after the Rules of Evidence went into effect, these rules are properly applied in determining the propriety of the district court’s evidentiary rulings.
. The toxicologist’s report revealed an overdose of multiple depressant drugs and ethanol.
. The appellant also points to Rule 803(9) which provided an exception to the hearsay rule for records of vital statistics and to Rule 901(b)(7) which pertains to the authentication of public records as an additional basis for the total admissibility of the documents involved in this case. However, these rules do not mandate the admission of evidence, but only provide a means for allowing into evidence documents which are otherwise admissible. See Advisory Committee’s Notes to Rule 803 and Rule 901(b).
. Although the policies restricted benefits to death which occurred solely through “violent, external and accidental” means, the Judge instructed the jury that death caused by the ingestion or consumption of drugs or a combination of drugs and alcohol is caused by violent and external means. Therefore, the key issue for jury determination was whether death was accidental.
. We do not reach the merits of the appellant’s contention that the trial judge’s charge to the jury on the meaning of preponderance of the evidence was erroneous. Appellant did not object to this instruction before the jury retired, and is therefore precluded under Rule 51 of the Federal Rules of Civil Procedure from assigning this as an error. Halij v. Fogarty, 449 F.2d 1295 (3d Cir. 1971); Jennings v. Boenning & Company, 388 F.Supp. 1294, 1303-1304 (E.D. Pa. 1975) aff. 523 F.2d 889 (3d Cir. 1975). See Paluch v. Erie Lackawanna Railroad Co., 387 F.2d 996, 999-1000 (3d Cir. 1968).